From 18186c32892f87fefbe37b7a1c52ad0cdbf26ee5 Mon Sep 17 00:00:00 2001
From: Cengizhan Pasaoglu <cengizhanpasaoglu@gmail.com>
Date: Tue, 6 Jun 2023 13:14:21 +0200
Subject: [PATCH 1/2] First draft of forward declaration applied in SDK folder

---
 .../trace/span_context_kv_iterable_view.h     |  2 +
 examples/batch/main.cc                        |  4 ++
 examples/grpc/tracer_common.h                 |  3 +
 examples/http/tracer_common.h                 |  3 +
 examples/jaeger/main.cc                       |  1 +
 examples/logs_simple/main.cc                  |  3 +
 examples/multithreaded/main.cc                |  2 +
 examples/otlp/grpc_log_main.cc                |  2 +
 examples/otlp/grpc_main.cc                    |  1 +
 examples/otlp/http_log_main.cc                |  2 +
 examples/otlp/http_main.cc                    |  1 +
 examples/simple/main.cc                       |  2 +
 examples/zipkin/main.cc                       |  2 +
 .../elasticsearch/src/es_log_recordable.cc    |  6 ++
 .../opentelemetry/exporters/etw/etw_tracer.h  |  1 +
 exporters/jaeger/src/recordable.cc            |  1 +
 exporters/jaeger/test/jaeger_exporter_test.cc | 10 +++-
 .../exporters/ostream/log_record_exporter.h   |  3 +
 .../exporters/ostream/metric_exporter.h       | 10 ++++
 exporters/ostream/src/log_record_exporter.cc  |  2 +
 exporters/ostream/src/metric_exporter.cc      | 12 ++--
 exporters/ostream/test/ostream_log_test.cc    |  5 +-
 exporters/ostream/test/ostream_metric_test.cc | 14 +++--
 exporters/otlp/src/otlp_metric_utils.cc       |  1 +
 .../otlp_grpc_log_record_exporter_test.cc     |  2 +
 .../otlp/test/otlp_http_exporter_test.cc      |  1 +
 .../test/otlp_http_metric_exporter_test.cc    |  2 +
 exporters/otlp/test/otlp_recordable_test.cc   |  1 +
 exporters/zipkin/src/recordable.cc            |  1 +
 exporters/zipkin/test/zipkin_exporter_test.cc |  4 +-
 ext/test/w3c_tracecontext_test/main.cc        |  1 +
 functional/otlp/func_http_main.cc             |  2 +
 .../sdk/common/atomic_shared_ptr.h            |  1 +
 .../sdk/common/attribute_utils.h              |  2 +
 .../sdk/common/attributemap_hash.h            |  7 ++-
 .../sdk/common/circular_buffer.h              |  1 +
 .../sdk/common/circular_buffer_range.h        |  2 -
 .../sdk/common/empty_attributes.h             |  8 +--
 .../sdk/common/global_log_handler.h           |  1 -
 .../instrumentation_library.h                 |  1 +
 .../instrumentation_scope.h                   |  8 +--
 .../sdk/logs/batch_log_record_processor.h     |  1 +
 .../logs/batch_log_record_processor_factory.h |  8 ++-
 .../logs/batch_log_record_processor_options.h |  4 +-
 .../opentelemetry/sdk/logs/event_logger.h     | 10 ++--
 .../sdk/logs/event_logger_provider.h          |  5 +-
 .../sdk/logs/event_logger_provider_factory.h  |  9 ++-
 sdk/include/opentelemetry/sdk/logs/exporter.h |  7 ++-
 sdk/include/opentelemetry/sdk/logs/logger.h   |  5 +-
 .../opentelemetry/sdk/logs/logger_context.h   |  5 +-
 .../sdk/logs/logger_context_factory.h         | 11 +++-
 .../opentelemetry/sdk/logs/logger_provider.h  | 11 ++--
 .../sdk/logs/logger_provider_factory.h        | 19 +++++--
 .../sdk/logs/multi_log_record_processor.h     |  4 +-
 .../logs/multi_log_record_processor_factory.h |  3 +-
 .../opentelemetry/sdk/logs/multi_recordable.h |  3 +-
 .../opentelemetry/sdk/logs/processor.h        |  5 +-
 .../sdk/logs/read_write_log_record.h          |  5 +-
 .../sdk/logs/readable_log_record.h            | 26 ++++++---
 .../opentelemetry/sdk/logs/recordable.h       | 22 ++++----
 .../sdk/logs/simple_log_record_processor.h    |  7 ++-
 .../simple_log_record_processor_factory.h     |  5 +-
 .../sdk/metrics/aggregation/aggregation.h     |  6 +-
 .../metrics/aggregation/aggregation_config.h  |  4 +-
 .../metrics/aggregation/default_aggregation.h |  7 +--
 .../metrics/aggregation/drop_aggregation.h    |  7 ++-
 .../aggregation/histogram_aggregation.h       |  8 ++-
 .../aggregation/lastvalue_aggregation.h       |  6 +-
 .../sdk/metrics/aggregation/sum_aggregation.h |  6 +-
 .../sdk/metrics/async_instruments.h           |  6 +-
 .../sdk/metrics/data/exemplar_data.h          |  3 +-
 .../sdk/metrics/data/metric_data.h            |  4 +-
 .../sdk/metrics/data/point_data.h             |  5 +-
 .../metrics/exemplar/always_sample_filter.h   |  6 ++
 .../sdk/metrics/exemplar/filter.h             | 14 ++++-
 .../exemplar/filtered_exemplar_reservoir.h    | 15 ++++-
 .../exemplar/fixed_size_exemplar_reservoir.h  |  1 +
 .../exemplar/histogram_exemplar_reservoir.h   | 15 ++++-
 .../metrics/exemplar/never_sample_filter.h    |  6 ++
 .../metrics/exemplar/no_exemplar_reservoir.h  | 19 ++++++-
 .../sdk/metrics/exemplar/reservoir.h          | 16 +++++-
 .../sdk/metrics/exemplar/reservoir_cell.h     | 12 ++--
 .../exemplar/reservoir_cell_selector.h        | 12 ++--
 .../exemplar/with_trace_sample_filter.h       |  1 +
 .../sdk/metrics/export/metric_producer.h      | 16 +++++-
 .../export/periodic_exporting_metric_reader.h |  8 ++-
 .../metrics/instrument_metadata_validator.h   |  1 +
 .../opentelemetry/sdk/metrics/instruments.h   |  4 +-
 sdk/include/opentelemetry/sdk/metrics/meter.h | 11 +++-
 .../opentelemetry/sdk/metrics/meter_context.h | 18 +++---
 .../sdk/metrics/meter_provider.h              | 18 ++++--
 .../opentelemetry/sdk/metrics/metric_reader.h | 11 ++--
 .../sdk/metrics/observer_result.h             |  5 +-
 .../sdk/metrics/push_metric_exporter.h        | 11 ++--
 .../sdk/metrics/state/async_metric_storage.h  |  6 +-
 .../sdk/metrics/state/metric_collector.h      |  6 +-
 .../sdk/metrics/state/metric_storage.h        | 18 +++++-
 .../sdk/metrics/state/multi_metric_storage.h  | 19 ++++++-
 .../sdk/metrics/state/observable_registry.h   |  7 ++-
 .../sdk/metrics/state/sync_metric_storage.h   | 16 ++++--
 .../metrics/state/temporal_metric_storage.h   | 17 ++++--
 .../sdk/metrics/sync_instruments.h            |  7 +--
 .../sdk/metrics/view/attributes_processor.h   |  7 +++
 .../sdk/metrics/view/instrument_selector.h    |  4 ++
 .../sdk/metrics/view/meter_selector.h         |  3 +
 .../sdk/metrics/view/predicate_factory.h      |  3 +
 .../opentelemetry/sdk/metrics/view/view.h     |  7 ++-
 .../sdk/metrics/view/view_registry.h          |  5 ++
 .../opentelemetry/sdk/resource/resource.h     |  9 +--
 .../sdk/resource/resource_detector.h          |  4 +-
 .../sdk/trace/batch_span_processor.h          | 14 +++--
 .../sdk/trace/batch_span_processor_factory.h  |  8 +--
 .../sdk/trace/batch_span_processor_options.h  |  4 +-
 .../opentelemetry/sdk/trace/exporter.h        |  9 ++-
 .../opentelemetry/sdk/trace/id_generator.h    |  1 +
 .../sdk/trace/multi_recordable.h              |  4 +-
 .../sdk/trace/multi_span_processor.h          |  5 +-
 .../opentelemetry/sdk/trace/processor.h       | 10 +++-
 .../sdk/trace/random_id_generator.h           |  2 +
 .../sdk/trace/random_id_generator_factory.h   |  3 +-
 .../opentelemetry/sdk/trace/recordable.h      | 20 ++++---
 sdk/include/opentelemetry/sdk/trace/sampler.h | 27 ++++++---
 .../sdk/trace/samplers/always_off.h           |  5 ++
 .../sdk/trace/samplers/always_off_factory.h   |  3 +-
 .../sdk/trace/samplers/always_on.h            | 15 +++++
 .../sdk/trace/samplers/always_on_factory.h    |  3 +-
 .../opentelemetry/sdk/trace/samplers/parent.h | 17 +++++-
 .../sdk/trace/samplers/parent_factory.h       |  3 +-
 .../sdk/trace/samplers/trace_id_ratio.h       | 18 ++++++
 .../trace/samplers/trace_id_ratio_factory.h   |  3 +-
 .../sdk/trace/simple_processor.h              |  5 ++
 .../sdk/trace/simple_processor_factory.h      |  5 +-
 .../opentelemetry/sdk/trace/span_data.h       |  9 ++-
 sdk/include/opentelemetry/sdk/trace/tracer.h  | 30 ++++++----
 .../opentelemetry/sdk/trace/tracer_context.h  |  5 +-
 .../sdk/trace/tracer_context_factory.h        | 15 ++++-
 .../opentelemetry/sdk/trace/tracer_provider.h | 26 +++++----
 .../sdk/trace/tracer_provider_factory.h       | 21 +++++--
 sdk/src/common/global_log_handler.cc          |  3 +-
 sdk/src/logs/batch_log_record_processor.cc    |  4 ++
 sdk/src/logs/logger.cc                        |  9 ++-
 sdk/src/logs/logger_context_factory.cc        |  3 +
 sdk/src/logs/logger_provider.cc               | 10 ++--
 sdk/src/logs/multi_log_record_processor.cc    |  6 +-
 sdk/src/logs/readable_log_record.cc           |  7 ++-
 sdk/src/logs/simple_log_record_processor.cc   |  7 ++-
 .../aggregation/histogram_aggregation.cc      |  1 +
 sdk/src/metrics/async_instruments.cc          |  3 +-
 sdk/src/metrics/meter_context.cc              |  4 +-
 sdk/src/metrics/meter_provider.cc             |  2 +
 sdk/src/metrics/metric_reader.cc              |  1 +
 .../metrics/state/temporal_metric_storage.cc  | 14 +++--
 sdk/src/resource/resource.cc                  |  1 +
 sdk/src/resource/resource_detector.cc         |  3 +
 sdk/src/trace/batch_span_processor.cc         |  5 ++
 sdk/src/trace/samplers/parent.cc              |  1 +
 sdk/src/trace/span.cc                         | 14 +++--
 sdk/src/trace/tracer.cc                       | 55 ++++++++++---------
 sdk/src/trace/tracer_provider.cc              |  3 +
 sdk/src/trace/tracer_provider_factory.cc      |  1 +
 sdk/test/logs/log_record_test.cc              |  1 +
 sdk/test/logs/logger_provider_sdk_test.cc     |  1 +
 sdk/test/logs/logger_sdk_test.cc              |  6 +-
 sdk/test/metrics/aggregation_test.cc          |  1 +
 sdk/test/metrics/async_instruments_test.cc    |  1 +
 .../metrics/attributes_hashmap_benchmark.cc   |  2 +
 .../exemplar/always_sample_filter_test.cc     |  2 +
 sdk/test/metrics/multi_metric_storage_test.cc |  1 -
 sdk/test/resource/resource_test.cc            |  5 +-
 sdk/test/trace/batch_span_processor_test.cc   |  4 ++
 sdk/test/trace/sampler_benchmark.cc           |  8 ++-
 sdk/test/trace/tracer_test.cc                 |  5 +-
 172 files changed, 856 insertions(+), 361 deletions(-)

diff --git a/api/include/opentelemetry/trace/span_context_kv_iterable_view.h b/api/include/opentelemetry/trace/span_context_kv_iterable_view.h
index c20155edd6..6a21aaf54a 100644
--- a/api/include/opentelemetry/trace/span_context_kv_iterable_view.h
+++ b/api/include/opentelemetry/trace/span_context_kv_iterable_view.h
@@ -9,8 +9,10 @@
 
 #include "opentelemetry/common/key_value_iterable_view.h"
 #include "opentelemetry/nostd/function_ref.h"
+#include "opentelemetry/nostd/span.h"
 #include "opentelemetry/nostd/string_view.h"
 #include "opentelemetry/nostd/utility.h"
+#include "opentelemetry/trace/span_context.h"
 #include "opentelemetry/trace/span_context_kv_iterable.h"
 #include "opentelemetry/version.h"
 
diff --git a/examples/batch/main.cc b/examples/batch/main.cc
index a417933247..0e05c1b700 100644
--- a/examples/batch/main.cc
+++ b/examples/batch/main.cc
@@ -2,7 +2,11 @@
 // SPDX-License-Identifier: Apache-2.0
 
 #include "opentelemetry/exporters/ostream/span_exporter_factory.h"
+#include "opentelemetry/sdk/resource/resource.h"
 #include "opentelemetry/sdk/trace/batch_span_processor_factory.h"
+#include "opentelemetry/sdk/trace/batch_span_processor_options.h"
+#include "opentelemetry/sdk/trace/exporter.h"
+#include "opentelemetry/sdk/trace/processor.h"
 #include "opentelemetry/sdk/trace/tracer_provider_factory.h"
 #include "opentelemetry/trace/provider.h"
 
diff --git a/examples/grpc/tracer_common.h b/examples/grpc/tracer_common.h
index 073bffd50a..347e7a8184 100644
--- a/examples/grpc/tracer_common.h
+++ b/examples/grpc/tracer_common.h
@@ -7,7 +7,10 @@
 #include "opentelemetry/context/propagation/text_map_propagator.h"
 #include "opentelemetry/exporters/ostream/span_exporter_factory.h"
 #include "opentelemetry/nostd/shared_ptr.h"
+#include "opentelemetry/sdk/trace/exporter.h"
+#include "opentelemetry/sdk/trace/processor.h"
 #include "opentelemetry/sdk/trace/simple_processor_factory.h"
+#include "opentelemetry/sdk/trace/tracer_context.h"
 #include "opentelemetry/sdk/trace/tracer_context_factory.h"
 #include "opentelemetry/sdk/trace/tracer_provider_factory.h"
 #include "opentelemetry/trace/propagation/http_trace_context.h"
diff --git a/examples/http/tracer_common.h b/examples/http/tracer_common.h
index 0b74d2ff8e..7d9f1ca571 100644
--- a/examples/http/tracer_common.h
+++ b/examples/http/tracer_common.h
@@ -4,7 +4,10 @@
 #pragma once
 
 #include "opentelemetry/exporters/ostream/span_exporter_factory.h"
+#include "opentelemetry/sdk/trace/exporter.h"
+#include "opentelemetry/sdk/trace/processor.h"
 #include "opentelemetry/sdk/trace/simple_processor_factory.h"
+#include "opentelemetry/sdk/trace/tracer_context.h"
 #include "opentelemetry/sdk/trace/tracer_context_factory.h"
 #include "opentelemetry/sdk/trace/tracer_provider_factory.h"
 #include "opentelemetry/trace/provider.h"
diff --git a/examples/jaeger/main.cc b/examples/jaeger/main.cc
index faa9758f02..1b60eaed2a 100644
--- a/examples/jaeger/main.cc
+++ b/examples/jaeger/main.cc
@@ -2,6 +2,7 @@
 // SPDX-License-Identifier: Apache-2.0
 
 #include "opentelemetry/exporters/jaeger/jaeger_exporter_factory.h"
+#include "opentelemetry/sdk/trace/processor.h"
 #include "opentelemetry/sdk/trace/simple_processor_factory.h"
 #include "opentelemetry/sdk/trace/tracer_provider_factory.h"
 #include "opentelemetry/trace/provider.h"
diff --git a/examples/logs_simple/main.cc b/examples/logs_simple/main.cc
index f4bcecbb39..c12733d4c3 100644
--- a/examples/logs_simple/main.cc
+++ b/examples/logs_simple/main.cc
@@ -3,6 +3,8 @@
 
 #ifdef ENABLE_LOGS_PREVIEW
 #  include "opentelemetry/exporters/ostream/span_exporter_factory.h"
+#  include "opentelemetry/sdk/trace/exporter.h"
+#  include "opentelemetry/sdk/trace/processor.h"
 #  include "opentelemetry/sdk/trace/simple_processor_factory.h"
 #  include "opentelemetry/sdk/trace/tracer_provider_factory.h"
 #  include "opentelemetry/trace/provider.h"
@@ -10,6 +12,7 @@
 #  include "opentelemetry/exporters/ostream/log_record_exporter.h"
 #  include "opentelemetry/logs/provider.h"
 #  include "opentelemetry/sdk/logs/logger_provider_factory.h"
+#  include "opentelemetry/sdk/logs/processor.h"
 #  include "opentelemetry/sdk/logs/simple_log_record_processor_factory.h"
 
 #  ifdef BAZEL_BUILD
diff --git a/examples/multithreaded/main.cc b/examples/multithreaded/main.cc
index 49eaf4d16d..6071e2597a 100644
--- a/examples/multithreaded/main.cc
+++ b/examples/multithreaded/main.cc
@@ -3,6 +3,8 @@
 
 #include "opentelemetry/exporters/ostream/span_exporter_factory.h"
 #include "opentelemetry/sdk/resource/resource.h"
+#include "opentelemetry/sdk/trace/exporter.h"
+#include "opentelemetry/sdk/trace/processor.h"
 #include "opentelemetry/sdk/trace/simple_processor_factory.h"
 #include "opentelemetry/sdk/trace/tracer_provider_factory.h"
 #include "opentelemetry/trace/provider.h"
diff --git a/examples/otlp/grpc_log_main.cc b/examples/otlp/grpc_log_main.cc
index e0c85c38c2..ffd4376ebf 100644
--- a/examples/otlp/grpc_log_main.cc
+++ b/examples/otlp/grpc_log_main.cc
@@ -6,7 +6,9 @@
 #  include "opentelemetry/exporters/otlp/otlp_grpc_log_record_exporter_factory.h"
 #  include "opentelemetry/logs/provider.h"
 #  include "opentelemetry/sdk/logs/logger_provider_factory.h"
+#  include "opentelemetry/sdk/logs/processor.h"
 #  include "opentelemetry/sdk/logs/simple_log_record_processor_factory.h"
+#  include "opentelemetry/sdk/trace/processor.h"
 #  include "opentelemetry/sdk/trace/simple_processor_factory.h"
 #  include "opentelemetry/sdk/trace/tracer_provider_factory.h"
 #  include "opentelemetry/trace/provider.h"
diff --git a/examples/otlp/grpc_main.cc b/examples/otlp/grpc_main.cc
index d7e3b29d6c..c238d9ad2a 100644
--- a/examples/otlp/grpc_main.cc
+++ b/examples/otlp/grpc_main.cc
@@ -2,6 +2,7 @@
 // SPDX-License-Identifier: Apache-2.0
 
 #include "opentelemetry/exporters/otlp/otlp_grpc_exporter_factory.h"
+#include "opentelemetry/sdk/trace/processor.h"
 #include "opentelemetry/sdk/trace/simple_processor_factory.h"
 #include "opentelemetry/sdk/trace/tracer_provider_factory.h"
 #include "opentelemetry/trace/provider.h"
diff --git a/examples/otlp/http_log_main.cc b/examples/otlp/http_log_main.cc
index a1171b04e0..5a5eeb599a 100644
--- a/examples/otlp/http_log_main.cc
+++ b/examples/otlp/http_log_main.cc
@@ -8,7 +8,9 @@
 #  include "opentelemetry/logs/provider.h"
 #  include "opentelemetry/sdk/common/global_log_handler.h"
 #  include "opentelemetry/sdk/logs/logger_provider_factory.h"
+#  include "opentelemetry/sdk/logs/processor.h"
 #  include "opentelemetry/sdk/logs/simple_log_record_processor_factory.h"
+#  include "opentelemetry/sdk/trace/processor.h"
 #  include "opentelemetry/sdk/trace/simple_processor_factory.h"
 #  include "opentelemetry/sdk/trace/tracer_provider_factory.h"
 #  include "opentelemetry/trace/provider.h"
diff --git a/examples/otlp/http_main.cc b/examples/otlp/http_main.cc
index 09b8daeee2..6a0667b918 100644
--- a/examples/otlp/http_main.cc
+++ b/examples/otlp/http_main.cc
@@ -4,6 +4,7 @@
 #include "opentelemetry/exporters/otlp/otlp_http_exporter_factory.h"
 #include "opentelemetry/exporters/otlp/otlp_http_exporter_options.h"
 #include "opentelemetry/sdk/common/global_log_handler.h"
+#include "opentelemetry/sdk/trace/processor.h"
 #include "opentelemetry/sdk/trace/simple_processor_factory.h"
 #include "opentelemetry/sdk/trace/tracer_provider_factory.h"
 #include "opentelemetry/trace/provider.h"
diff --git a/examples/simple/main.cc b/examples/simple/main.cc
index 6a8b28e4dd..48768b6448 100644
--- a/examples/simple/main.cc
+++ b/examples/simple/main.cc
@@ -2,6 +2,8 @@
 // SPDX-License-Identifier: Apache-2.0
 
 #include "opentelemetry/exporters/ostream/span_exporter_factory.h"
+#include "opentelemetry/sdk/trace/exporter.h"
+#include "opentelemetry/sdk/trace/processor.h"
 #include "opentelemetry/sdk/trace/simple_processor_factory.h"
 #include "opentelemetry/sdk/trace/tracer_provider_factory.h"
 #include "opentelemetry/trace/provider.h"
diff --git a/examples/zipkin/main.cc b/examples/zipkin/main.cc
index 6788d8cabe..0052cd430e 100644
--- a/examples/zipkin/main.cc
+++ b/examples/zipkin/main.cc
@@ -2,6 +2,8 @@
 // SPDX-License-Identifier: Apache-2.0
 
 #include "opentelemetry/exporters/zipkin/zipkin_exporter_factory.h"
+#include "opentelemetry/sdk/resource/resource.h"
+#include "opentelemetry/sdk/trace/processor.h"
 #include "opentelemetry/sdk/trace/simple_processor_factory.h"
 #include "opentelemetry/sdk/trace/tracer_provider_factory.h"
 #include "opentelemetry/trace/provider.h"
diff --git a/exporters/elasticsearch/src/es_log_recordable.cc b/exporters/elasticsearch/src/es_log_recordable.cc
index 03c6c640e5..e3f60be0a9 100644
--- a/exporters/elasticsearch/src/es_log_recordable.cc
+++ b/exporters/elasticsearch/src/es_log_recordable.cc
@@ -4,6 +4,12 @@
 #ifdef ENABLE_LOGS_PREVIEW
 
 #  include "opentelemetry/exporters/elasticsearch/es_log_recordable.h"
+#  include "opentelemetry/logs/severity.h"
+#  include "opentelemetry/sdk/instrumentationscope/instrumentation_scope.h"
+#  include "opentelemetry/sdk/resource/resource.h"
+#  include "opentelemetry/trace/span_id.h"
+#  include "opentelemetry/trace/trace_flags.h"
+#  include "opentelemetry/trace/trace_id.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace exporter
diff --git a/exporters/etw/include/opentelemetry/exporters/etw/etw_tracer.h b/exporters/etw/include/opentelemetry/exporters/etw/etw_tracer.h
index 039351f66e..6601f850df 100644
--- a/exporters/etw/include/opentelemetry/exporters/etw/etw_tracer.h
+++ b/exporters/etw/include/opentelemetry/exporters/etw/etw_tracer.h
@@ -32,6 +32,7 @@
 #include "opentelemetry/trace/trace_id.h"
 #include "opentelemetry/trace/tracer_provider.h"
 
+#include "opentelemetry/sdk/common/empty_attributes.h"
 #include "opentelemetry/sdk/trace/exporter.h"
 #include "opentelemetry/sdk/trace/samplers/always_on.h"
 
diff --git a/exporters/jaeger/src/recordable.cc b/exporters/jaeger/src/recordable.cc
index d147d96553..1fd7e99dff 100644
--- a/exporters/jaeger/src/recordable.cc
+++ b/exporters/jaeger/src/recordable.cc
@@ -3,6 +3,7 @@
 
 #include "opentelemetry/exporters/jaeger/recordable.h"
 #include "opentelemetry/sdk/common/global_log_handler.h"
+#include "opentelemetry/sdk/resource/resource.h"
 #include "opentelemetry/sdk/resource/semantic_conventions.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
diff --git a/exporters/jaeger/test/jaeger_exporter_test.cc b/exporters/jaeger/test/jaeger_exporter_test.cc
index 7f86f877bc..ea305267c5 100644
--- a/exporters/jaeger/test/jaeger_exporter_test.cc
+++ b/exporters/jaeger/test/jaeger_exporter_test.cc
@@ -1,11 +1,12 @@
 // Copyright The OpenTelemetry Authors
 // SPDX-License-Identifier: Apache-2.0
 
-#include <opentelemetry/exporters/jaeger/jaeger_exporter.h>
-#include <memory>
-#include <vector>
+#include "opentelemetry/exporters/jaeger/jaeger_exporter.h"
 #include "opentelemetry/sdk/trace/batch_span_processor.h"
+#include "opentelemetry/sdk/trace/batch_span_processor_options.h"
+#include "opentelemetry/sdk/trace/tracer.h"
 #include "opentelemetry/sdk/trace/tracer_provider.h"
+#include "opentelemetry/trace/span_startoptions.h"
 
 #ifdef BAZEL_BUILD
 #  include "exporters/jaeger/src/thrift_sender.h"
@@ -16,6 +17,9 @@
 #include <gtest/gtest.h>
 #include "gmock/gmock.h"
 
+#include <memory>
+#include <vector>
+
 namespace trace      = opentelemetry::trace;
 namespace nostd      = opentelemetry::nostd;
 namespace sdktrace   = opentelemetry::sdk::trace;
diff --git a/exporters/ostream/include/opentelemetry/exporters/ostream/log_record_exporter.h b/exporters/ostream/include/opentelemetry/exporters/ostream/log_record_exporter.h
index 34806bd200..54dae898d2 100644
--- a/exporters/ostream/include/opentelemetry/exporters/ostream/log_record_exporter.h
+++ b/exporters/ostream/include/opentelemetry/exporters/ostream/log_record_exporter.h
@@ -4,14 +4,17 @@
 #pragma once
 #ifdef ENABLE_LOGS_PREVIEW
 
+#  include "opentelemetry/common/attribute_value.h"
 #  include "opentelemetry/common/spin_lock_mutex.h"
 #  include "opentelemetry/nostd/type_traits.h"
+#  include "opentelemetry/sdk/common/attribute_utils.h"
 #  include "opentelemetry/sdk/logs/exporter.h"
 
 #  include "opentelemetry/version.h"
 
 #  include <iostream>
 #  include <sstream>
+#  include <unordered_map>
 
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace exporter
diff --git a/exporters/ostream/include/opentelemetry/exporters/ostream/metric_exporter.h b/exporters/ostream/include/opentelemetry/exporters/ostream/metric_exporter.h
index 36e5917457..92419fdea0 100644
--- a/exporters/ostream/include/opentelemetry/exporters/ostream/metric_exporter.h
+++ b/exporters/ostream/include/opentelemetry/exporters/ostream/metric_exporter.h
@@ -5,13 +5,23 @@
 
 #include <iostream>
 #include <string>
+
 #include "opentelemetry/common/spin_lock_mutex.h"
 #include "opentelemetry/sdk/metrics/data/metric_data.h"
+#include "opentelemetry/sdk/metrics/export/metric_producer.h"
 #include "opentelemetry/sdk/metrics/instruments.h"
 #include "opentelemetry/sdk/metrics/push_metric_exporter.h"
 #include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
+namespace sdk
+{
+namespace resource
+{
+class Resource;
+}  // namespace resource
+}  // namespace sdk
+
 namespace exporter
 {
 namespace metrics
diff --git a/exporters/ostream/src/log_record_exporter.cc b/exporters/ostream/src/log_record_exporter.cc
index 18552d7a65..611a749184 100644
--- a/exporters/ostream/src/log_record_exporter.cc
+++ b/exporters/ostream/src/log_record_exporter.cc
@@ -4,7 +4,9 @@
 #ifdef ENABLE_LOGS_PREVIEW
 #  include "opentelemetry/exporters/ostream/log_record_exporter.h"
 #  include "opentelemetry/exporters/ostream/common_utils.h"
+#  include "opentelemetry/sdk/instrumentationscope/instrumentation_scope.h"
 #  include "opentelemetry/sdk/logs/read_write_log_record.h"
+#  include "opentelemetry/sdk/resource/resource.h"
 #  include "opentelemetry/sdk_config.h"
 
 #  include <iostream>
diff --git a/exporters/ostream/src/metric_exporter.cc b/exporters/ostream/src/metric_exporter.cc
index d963c4f420..003aaa075f 100644
--- a/exporters/ostream/src/metric_exporter.cc
+++ b/exporters/ostream/src/metric_exporter.cc
@@ -2,15 +2,19 @@
 // SPDX-License-Identifier: Apache-2.0
 
 #include "opentelemetry/exporters/ostream/metric_exporter.h"
-#include <algorithm>
-#include <chrono>
-#include <ctime>
-#include <map>
 #include "opentelemetry/exporters/ostream/common_utils.h"
+#include "opentelemetry/sdk/instrumentationscope/instrumentation_scope.h"
 #include "opentelemetry/sdk/metrics/aggregation/default_aggregation.h"
 #include "opentelemetry/sdk/metrics/aggregation/histogram_aggregation.h"
+#include "opentelemetry/sdk/resource/resource.h"
 #include "opentelemetry/sdk_config.h"
 
+#include <algorithm>
+#include <chrono>
+#include <ctime>
+#include <map>
+#include <mutex>
+
 namespace
 {
 std::string timeToString(opentelemetry::common::SystemTimestamp time_stamp)
diff --git a/exporters/ostream/test/ostream_log_test.cc b/exporters/ostream/test/ostream_log_test.cc
index 82bc91a747..92ff3ece76 100644
--- a/exporters/ostream/test/ostream_log_test.cc
+++ b/exporters/ostream/test/ostream_log_test.cc
@@ -3,15 +3,18 @@
 
 #ifdef ENABLE_LOGS_PREVIEW
 
-#  include <array>
 #  include "opentelemetry/exporters/ostream/log_record_exporter.h"
 #  include "opentelemetry/logs/provider.h"
 #  include "opentelemetry/nostd/span.h"
+#  include "opentelemetry/sdk/instrumentationscope/instrumentation_scope.h"
 #  include "opentelemetry/sdk/logs/logger_provider.h"
 #  include "opentelemetry/sdk/logs/read_write_log_record.h"
 #  include "opentelemetry/sdk/logs/simple_log_record_processor.h"
+#  include "opentelemetry/sdk/version/version.h"
 
 #  include <gtest/gtest.h>
+
+#  include <array>
 #  include <iostream>
 
 namespace sdklogs      = opentelemetry::sdk::logs;
diff --git a/exporters/ostream/test/ostream_metric_test.cc b/exporters/ostream/test/ostream_metric_test.cc
index cb4a8a3ab4..17fbcb5880 100644
--- a/exporters/ostream/test/ostream_metric_test.cc
+++ b/exporters/ostream/test/ostream_metric_test.cc
@@ -2,18 +2,20 @@
 // SPDX-License-Identifier: Apache-2.0
 
 #include <gtest/gtest.h>
-#include <memory>
-#include <vector>
-#include "opentelemetry/sdk/metrics/instruments.h"
-#include "opentelemetry/sdk/resource/resource_detector.h"
-#include "opentelemetry/sdk/version/version.h"
 
-#include <iostream>
 #include "opentelemetry/exporters/ostream/metric_exporter.h"
+#include "opentelemetry/sdk/instrumentationscope/instrumentation_scope.h"
 #include "opentelemetry/sdk/metrics/aggregation/default_aggregation.h"
 #include "opentelemetry/sdk/metrics/aggregation/histogram_aggregation.h"
 #include "opentelemetry/sdk/metrics/data/metric_data.h"
+#include "opentelemetry/sdk/metrics/instruments.h"
 #include "opentelemetry/sdk/resource/resource.h"
+#include "opentelemetry/sdk/resource/resource_detector.h"
+#include "opentelemetry/sdk/version/version.h"
+
+#include <iostream>
+#include <memory>
+#include <vector>
 
 namespace metric_sdk      = opentelemetry::sdk::metrics;
 namespace nostd           = opentelemetry::nostd;
diff --git a/exporters/otlp/src/otlp_metric_utils.cc b/exporters/otlp/src/otlp_metric_utils.cc
index 4f56c2f356..f642bbf85e 100644
--- a/exporters/otlp/src/otlp_metric_utils.cc
+++ b/exporters/otlp/src/otlp_metric_utils.cc
@@ -3,6 +3,7 @@
 
 #include "opentelemetry/exporters/otlp/otlp_metric_utils.h"
 #include "opentelemetry/exporters/otlp/otlp_populate_attribute_utils.h"
+#include "opentelemetry/sdk/instrumentationscope/instrumentation_scope.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
 
diff --git a/exporters/otlp/test/otlp_grpc_log_record_exporter_test.cc b/exporters/otlp/test/otlp_grpc_log_record_exporter_test.cc
index f2962a0b0c..f2ed416327 100644
--- a/exporters/otlp/test/otlp_grpc_log_record_exporter_test.cc
+++ b/exporters/otlp/test/otlp_grpc_log_record_exporter_test.cc
@@ -19,8 +19,10 @@
 #  include "opentelemetry/sdk/logs/batch_log_record_processor.h"
 #  include "opentelemetry/sdk/logs/exporter.h"
 #  include "opentelemetry/sdk/logs/logger_provider.h"
+#  include "opentelemetry/sdk/logs/recordable.h"
 #  include "opentelemetry/sdk/resource/resource.h"
 #  include "opentelemetry/sdk/trace/exporter.h"
+#  include "opentelemetry/sdk/trace/processor.h"
 #  include "opentelemetry/sdk/trace/simple_processor_factory.h"
 #  include "opentelemetry/sdk/trace/tracer_provider_factory.h"
 #  include "opentelemetry/trace/provider.h"
diff --git a/exporters/otlp/test/otlp_http_exporter_test.cc b/exporters/otlp/test/otlp_http_exporter_test.cc
index 9c5bfe1766..2ac698b0de 100644
--- a/exporters/otlp/test/otlp_http_exporter_test.cc
+++ b/exporters/otlp/test/otlp_http_exporter_test.cc
@@ -17,6 +17,7 @@
 #  include "opentelemetry/ext/http/client/http_client_factory.h"
 #  include "opentelemetry/ext/http/server/http_server.h"
 #  include "opentelemetry/sdk/trace/batch_span_processor.h"
+#  include "opentelemetry/sdk/trace/batch_span_processor_options.h"
 #  include "opentelemetry/sdk/trace/tracer_provider.h"
 #  include "opentelemetry/test_common/ext/http/client/nosend/http_client_nosend.h"
 #  include "opentelemetry/trace/provider.h"
diff --git a/exporters/otlp/test/otlp_http_metric_exporter_test.cc b/exporters/otlp/test/otlp_http_metric_exporter_test.cc
index c47c86e110..97586b101c 100644
--- a/exporters/otlp/test/otlp_http_metric_exporter_test.cc
+++ b/exporters/otlp/test/otlp_http_metric_exporter_test.cc
@@ -16,9 +16,11 @@
 #include "opentelemetry/common/key_value_iterable_view.h"
 #include "opentelemetry/ext/http/client/http_client_factory.h"
 #include "opentelemetry/ext/http/server/http_server.h"
+#include "opentelemetry/sdk/instrumentationscope/instrumentation_scope.h"
 #include "opentelemetry/sdk/metrics/aggregation/default_aggregation.h"
 #include "opentelemetry/sdk/metrics/aggregation/histogram_aggregation.h"
 #include "opentelemetry/sdk/metrics/data/metric_data.h"
+#include "opentelemetry/sdk/metrics/export/metric_producer.h"
 #include "opentelemetry/sdk/metrics/instruments.h"
 #include "opentelemetry/sdk/resource/resource.h"
 #include "opentelemetry/test_common/ext/http/client/nosend/http_client_nosend.h"
diff --git a/exporters/otlp/test/otlp_recordable_test.cc b/exporters/otlp/test/otlp_recordable_test.cc
index f1b1c73741..4db58844f7 100644
--- a/exporters/otlp/test/otlp_recordable_test.cc
+++ b/exporters/otlp/test/otlp_recordable_test.cc
@@ -2,6 +2,7 @@
 // SPDX-License-Identifier: Apache-2.0
 
 #include "opentelemetry/exporters/otlp/otlp_recordable.h"
+#include "opentelemetry/sdk/resource/resource.h"
 
 #if defined(__GNUC__)
 // GCC raises -Wsuggest-override warnings on GTest,
diff --git a/exporters/zipkin/src/recordable.cc b/exporters/zipkin/src/recordable.cc
index 96b486e51e..3397053e29 100644
--- a/exporters/zipkin/src/recordable.cc
+++ b/exporters/zipkin/src/recordable.cc
@@ -2,6 +2,7 @@
 // SPDX-License-Identifier: Apache-2.0
 
 #include "opentelemetry/exporters/zipkin/recordable.h"
+#include "opentelemetry/sdk/resource/resource.h"
 #include "opentelemetry/sdk/resource/semantic_conventions.h"
 
 #include <map>
diff --git a/exporters/zipkin/test/zipkin_exporter_test.cc b/exporters/zipkin/test/zipkin_exporter_test.cc
index f8493bec6d..fab19efb65 100644
--- a/exporters/zipkin/test/zipkin_exporter_test.cc
+++ b/exporters/zipkin/test/zipkin_exporter_test.cc
@@ -4,10 +4,10 @@
 #ifndef HAVE_CPP_STDLIB
 
 #  include "opentelemetry/exporters/zipkin/zipkin_exporter.h"
-#  include <string>
 #  include "opentelemetry/ext/http/client/curl/http_client_curl.h"
 #  include "opentelemetry/ext/http/server/http_server.h"
 #  include "opentelemetry/sdk/trace/batch_span_processor.h"
+#  include "opentelemetry/sdk/trace/batch_span_processor_options.h"
 #  include "opentelemetry/sdk/trace/tracer_provider.h"
 #  include "opentelemetry/trace/provider.h"
 
@@ -16,6 +16,8 @@
 
 #  include "nlohmann/json.hpp"
 
+#  include <string>
+
 #  if defined(_MSC_VER)
 #    include "opentelemetry/sdk/common/env_variables.h"
 using opentelemetry::sdk::common::setenv;
diff --git a/ext/test/w3c_tracecontext_test/main.cc b/ext/test/w3c_tracecontext_test/main.cc
index 562f45f107..92807dd8ad 100644
--- a/ext/test/w3c_tracecontext_test/main.cc
+++ b/ext/test/w3c_tracecontext_test/main.cc
@@ -6,6 +6,7 @@
 #include "opentelemetry/ext/http/client/curl/http_client_curl.h"
 #include "opentelemetry/ext/http/server/http_server.h"
 #include "opentelemetry/sdk/trace/simple_processor.h"
+#include "opentelemetry/sdk/trace/tracer_context.h"
 #include "opentelemetry/sdk/trace/tracer_provider.h"
 #include "opentelemetry/trace/propagation/http_trace_context.h"
 #include "opentelemetry/trace/provider.h"
diff --git a/functional/otlp/func_http_main.cc b/functional/otlp/func_http_main.cc
index 72fbb5e21c..cfe12a2707 100644
--- a/functional/otlp/func_http_main.cc
+++ b/functional/otlp/func_http_main.cc
@@ -4,10 +4,12 @@
 #include "opentelemetry/exporters/otlp/otlp_http_exporter_factory.h"
 #include "opentelemetry/exporters/otlp/otlp_http_exporter_options.h"
 #include "opentelemetry/sdk/common/global_log_handler.h"
+#include "opentelemetry/sdk/trace/processor.h"
 #include "opentelemetry/sdk/trace/simple_processor_factory.h"
 #include "opentelemetry/sdk/trace/tracer_provider_factory.h"
 #include "opentelemetry/trace/provider.h"
 
+#include <iostream>
 #include <string>
 
 namespace trace     = opentelemetry::trace;
diff --git a/sdk/include/opentelemetry/sdk/common/atomic_shared_ptr.h b/sdk/include/opentelemetry/sdk/common/atomic_shared_ptr.h
index 07e19ac0f8..39c0ce91cc 100644
--- a/sdk/include/opentelemetry/sdk/common/atomic_shared_ptr.h
+++ b/sdk/include/opentelemetry/sdk/common/atomic_shared_ptr.h
@@ -6,6 +6,7 @@
 #include <atomic>
 #include <memory>
 #include <mutex>
+
 #include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
diff --git a/sdk/include/opentelemetry/sdk/common/attribute_utils.h b/sdk/include/opentelemetry/sdk/common/attribute_utils.h
index b7839bddc7..c8afd657e2 100644
--- a/sdk/include/opentelemetry/sdk/common/attribute_utils.h
+++ b/sdk/include/opentelemetry/sdk/common/attribute_utils.h
@@ -7,8 +7,10 @@
 #include <string>
 #include <unordered_map>
 #include <vector>
+
 #include "opentelemetry/common/attribute_value.h"
 #include "opentelemetry/common/key_value_iterable_view.h"
+#include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
diff --git a/sdk/include/opentelemetry/sdk/common/attributemap_hash.h b/sdk/include/opentelemetry/sdk/common/attributemap_hash.h
index 086f6b7901..408070255a 100644
--- a/sdk/include/opentelemetry/sdk/common/attributemap_hash.h
+++ b/sdk/include/opentelemetry/sdk/common/attributemap_hash.h
@@ -3,8 +3,13 @@
 
 #pragma once
 
-#include <string>
+#include <functional>
+
+#include "opentelemetry/nostd/function_ref.h"
+#include "opentelemetry/nostd/string_view.h"
+#include "opentelemetry/nostd/variant.h"
 #include "opentelemetry/sdk/common/attribute_utils.h"
+#include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
diff --git a/sdk/include/opentelemetry/sdk/common/circular_buffer.h b/sdk/include/opentelemetry/sdk/common/circular_buffer.h
index 9f34659352..c2548012b1 100644
--- a/sdk/include/opentelemetry/sdk/common/circular_buffer.h
+++ b/sdk/include/opentelemetry/sdk/common/circular_buffer.h
@@ -4,6 +4,7 @@
 #pragma once
 
 #include <atomic>
+#include <cassert>
 #include <cstdint>
 #include <memory>
 
diff --git a/sdk/include/opentelemetry/sdk/common/circular_buffer_range.h b/sdk/include/opentelemetry/sdk/common/circular_buffer_range.h
index 9ef3b66be0..e9b89f9d02 100644
--- a/sdk/include/opentelemetry/sdk/common/circular_buffer_range.h
+++ b/sdk/include/opentelemetry/sdk/common/circular_buffer_range.h
@@ -4,8 +4,6 @@
 #pragma once
 
 #include <cassert>
-#include <iterator>
-#include <type_traits>
 #include <utility>
 
 #include "opentelemetry/nostd/span.h"
diff --git a/sdk/include/opentelemetry/sdk/common/empty_attributes.h b/sdk/include/opentelemetry/sdk/common/empty_attributes.h
index 4f740bf10e..664f907d23 100644
--- a/sdk/include/opentelemetry/sdk/common/empty_attributes.h
+++ b/sdk/include/opentelemetry/sdk/common/empty_attributes.h
@@ -3,14 +3,14 @@
 
 #pragma once
 
-#include "opentelemetry/common/key_value_iterable_view.h"
-#include "opentelemetry/common/macros.h"
-
 #include <array>
-#include <map>
 #include <string>
 #include <utility>
 
+#include "opentelemetry/common/key_value_iterable_view.h"
+#include "opentelemetry/common/macros.h"
+#include "opentelemetry/version.h"
+
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
 {
diff --git a/sdk/include/opentelemetry/sdk/common/global_log_handler.h b/sdk/include/opentelemetry/sdk/common/global_log_handler.h
index 56103d3818..74dd90ccc6 100644
--- a/sdk/include/opentelemetry/sdk/common/global_log_handler.h
+++ b/sdk/include/opentelemetry/sdk/common/global_log_handler.h
@@ -3,7 +3,6 @@
 
 #pragma once
 
-#include <iostream>
 #include <sstream>
 #include <utility>
 
diff --git a/sdk/include/opentelemetry/sdk/instrumentationlibrary/instrumentation_library.h b/sdk/include/opentelemetry/sdk/instrumentationlibrary/instrumentation_library.h
index 8a7f9b808a..52f58c6f4e 100644
--- a/sdk/include/opentelemetry/sdk/instrumentationlibrary/instrumentation_library.h
+++ b/sdk/include/opentelemetry/sdk/instrumentationlibrary/instrumentation_library.h
@@ -4,6 +4,7 @@
 #pragma once
 
 #include "opentelemetry/sdk/instrumentationscope/instrumentation_scope.h"
+#include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
 
diff --git a/sdk/include/opentelemetry/sdk/instrumentationscope/instrumentation_scope.h b/sdk/include/opentelemetry/sdk/instrumentationscope/instrumentation_scope.h
index 5d75e61f75..9bae218ba4 100644
--- a/sdk/include/opentelemetry/sdk/instrumentationscope/instrumentation_scope.h
+++ b/sdk/include/opentelemetry/sdk/instrumentationscope/instrumentation_scope.h
@@ -3,16 +3,16 @@
 
 #pragma once
 
-#include "opentelemetry/common/key_value_iterable.h"
+#include <string>
+
 #include "opentelemetry/common/key_value_iterable_view.h"
 #include "opentelemetry/nostd/string_view.h"
+#include "opentelemetry/nostd/type_traits.h"
 #include "opentelemetry/nostd/unique_ptr.h"
+#include "opentelemetry/nostd/variant.h"
 #include "opentelemetry/sdk/common/attribute_utils.h"
 #include "opentelemetry/version.h"
 
-#include <functional>
-#include <string>
-
 OPENTELEMETRY_BEGIN_NAMESPACE
 
 namespace sdk
diff --git a/sdk/include/opentelemetry/sdk/logs/batch_log_record_processor.h b/sdk/include/opentelemetry/sdk/logs/batch_log_record_processor.h
index d13e8782f1..23a1d947aa 100644
--- a/sdk/include/opentelemetry/sdk/logs/batch_log_record_processor.h
+++ b/sdk/include/opentelemetry/sdk/logs/batch_log_record_processor.h
@@ -8,6 +8,7 @@
 #  include "opentelemetry/sdk/logs/batch_log_record_processor_options.h"
 #  include "opentelemetry/sdk/logs/exporter.h"
 #  include "opentelemetry/sdk/logs/processor.h"
+#  include "opentelemetry/version.h"
 
 #  include <atomic>
 #  include <condition_variable>
diff --git a/sdk/include/opentelemetry/sdk/logs/batch_log_record_processor_factory.h b/sdk/include/opentelemetry/sdk/logs/batch_log_record_processor_factory.h
index 55adc68f72..83740542cb 100644
--- a/sdk/include/opentelemetry/sdk/logs/batch_log_record_processor_factory.h
+++ b/sdk/include/opentelemetry/sdk/logs/batch_log_record_processor_factory.h
@@ -7,9 +7,7 @@
 
 #  include <memory>
 
-#  include "opentelemetry/sdk/logs/batch_log_record_processor_options.h"
-#  include "opentelemetry/sdk/logs/exporter.h"
-#  include "opentelemetry/sdk/logs/processor.h"
+#  include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
@@ -18,6 +16,10 @@ namespace sdk
 namespace logs
 {
 
+struct BatchLogRecordProcessorOptions;
+class LogRecordExporter;
+class LogRecordProcessor;
+
 /**
  * Factory class for BatchLogRecordProcessor.
  */
diff --git a/sdk/include/opentelemetry/sdk/logs/batch_log_record_processor_options.h b/sdk/include/opentelemetry/sdk/logs/batch_log_record_processor_options.h
index 1449bb48dc..05a2c48c3c 100644
--- a/sdk/include/opentelemetry/sdk/logs/batch_log_record_processor_options.h
+++ b/sdk/include/opentelemetry/sdk/logs/batch_log_record_processor_options.h
@@ -5,11 +5,11 @@
 
 #ifdef ENABLE_LOGS_PREVIEW
 
-#  include "opentelemetry/sdk/version/version.h"
-
 #  include <chrono>
 #  include <cstddef>
 
+#  include "opentelemetry/version.h"
+
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
 {
diff --git a/sdk/include/opentelemetry/sdk/logs/event_logger.h b/sdk/include/opentelemetry/sdk/logs/event_logger.h
index 85ad924766..b15754940a 100644
--- a/sdk/include/opentelemetry/sdk/logs/event_logger.h
+++ b/sdk/include/opentelemetry/sdk/logs/event_logger.h
@@ -4,19 +4,21 @@
 #pragma once
 #ifdef ENABLE_LOGS_PREVIEW
 
-#  include <memory>
-#  include <vector>
+#  include <string>
 
-#  include "opentelemetry/common/macros.h"
 #  include "opentelemetry/logs/event_logger.h"
-#  include "opentelemetry/logs/logger.h"
+#  include "opentelemetry/nostd/shared_ptr.h"
+#  include "opentelemetry/nostd/string_view.h"
 #  include "opentelemetry/nostd/unique_ptr.h"
+#  include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
 {
 namespace logs
 {
+class Logger;
+class LogRecord;
 
 class EventLogger final : public opentelemetry::logs::EventLogger
 {
diff --git a/sdk/include/opentelemetry/sdk/logs/event_logger_provider.h b/sdk/include/opentelemetry/sdk/logs/event_logger_provider.h
index ba12d94600..0eb9435f45 100644
--- a/sdk/include/opentelemetry/sdk/logs/event_logger_provider.h
+++ b/sdk/include/opentelemetry/sdk/logs/event_logger_provider.h
@@ -5,9 +5,9 @@
 #ifdef ENABLE_LOGS_PREVIEW
 
 #  include "opentelemetry/logs/event_logger_provider.h"
-#  include "opentelemetry/logs/logger.h"
 #  include "opentelemetry/nostd/shared_ptr.h"
-#  include "opentelemetry/sdk/logs/logger.h"
+#  include "opentelemetry/nostd/string_view.h"
+#  include "opentelemetry/version.h"
 
 // Define the maximum number of loggers that are allowed to be registered to the loggerprovider.
 // TODO: Add link to logging spec once this is added to it
@@ -18,6 +18,7 @@ namespace sdk
 {
 namespace logs
 {
+class EventLogger;
 class Logger;
 
 class EventLoggerProvider final : public opentelemetry::logs::EventLoggerProvider
diff --git a/sdk/include/opentelemetry/sdk/logs/event_logger_provider_factory.h b/sdk/include/opentelemetry/sdk/logs/event_logger_provider_factory.h
index 06aa1c4f2e..ecc78d1b80 100644
--- a/sdk/include/opentelemetry/sdk/logs/event_logger_provider_factory.h
+++ b/sdk/include/opentelemetry/sdk/logs/event_logger_provider_factory.h
@@ -5,10 +5,15 @@
 
 #ifdef ENABLE_LOGS_PREVIEW
 
-#  include "opentelemetry/logs/event_logger_provider.h"
-#  include "opentelemetry/nostd/shared_ptr.h"
+#  include <memory>
+#  include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
+namespace logs
+{
+class EventLoggerProvider;
+}  // namespace logs
+
 namespace sdk
 {
 namespace logs
diff --git a/sdk/include/opentelemetry/sdk/logs/exporter.h b/sdk/include/opentelemetry/sdk/logs/exporter.h
index 069fd8784c..fc0e68564c 100644
--- a/sdk/include/opentelemetry/sdk/logs/exporter.h
+++ b/sdk/include/opentelemetry/sdk/logs/exporter.h
@@ -4,19 +4,20 @@
 #pragma once
 #ifdef ENABLE_LOGS_PREVIEW
 
+#  include <chrono>
 #  include <memory>
-#  include <vector>
 
 #  include "opentelemetry/nostd/span.h"
 #  include "opentelemetry/sdk/common/exporter_utils.h"
-#  include "opentelemetry/sdk/logs/processor.h"
-#  include "opentelemetry/sdk/logs/recordable.h"
+#  include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
 {
 namespace logs
 {
+class Recordable;
+
 /**
  * LogRecordExporter defines the interface that log exporters must implement.
  */
diff --git a/sdk/include/opentelemetry/sdk/logs/logger.h b/sdk/include/opentelemetry/sdk/logs/logger.h
index d290df98c3..67eafe84bc 100644
--- a/sdk/include/opentelemetry/sdk/logs/logger.h
+++ b/sdk/include/opentelemetry/sdk/logs/logger.h
@@ -5,14 +5,15 @@
 #ifdef ENABLE_LOGS_PREVIEW
 
 #  include <memory>
-#  include <vector>
+#  include <string>
 
 #  include "opentelemetry/common/macros.h"
 #  include "opentelemetry/logs/logger.h"
+#  include "opentelemetry/nostd/string_view.h"
 #  include "opentelemetry/nostd/unique_ptr.h"
 #  include "opentelemetry/sdk/instrumentationscope/instrumentation_scope.h"
 #  include "opentelemetry/sdk/logs/logger_context.h"
-#  include "opentelemetry/sdk/logs/logger_provider.h"
+#  include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
diff --git a/sdk/include/opentelemetry/sdk/logs/logger_context.h b/sdk/include/opentelemetry/sdk/logs/logger_context.h
index fe6db6822a..0b2de9bc15 100644
--- a/sdk/include/opentelemetry/sdk/logs/logger_context.h
+++ b/sdk/include/opentelemetry/sdk/logs/logger_context.h
@@ -5,9 +5,10 @@
 
 #ifdef ENABLE_LOGS_PREVIEW
 
+#  include <chrono>
 #  include <memory>
+#  include <vector>
 
-#  include "opentelemetry/sdk/logs/processor.h"
 #  include "opentelemetry/sdk/resource/resource.h"
 #  include "opentelemetry/version.h"
 
@@ -16,6 +17,8 @@ namespace sdk
 {
 namespace logs
 {
+class LogRecordProcessor;
+
 /**
  * A class which stores the LoggerContext context.
  *
diff --git a/sdk/include/opentelemetry/sdk/logs/logger_context_factory.h b/sdk/include/opentelemetry/sdk/logs/logger_context_factory.h
index 377094d5db..0e3502c10c 100644
--- a/sdk/include/opentelemetry/sdk/logs/logger_context_factory.h
+++ b/sdk/include/opentelemetry/sdk/logs/logger_context_factory.h
@@ -6,17 +6,22 @@
 #ifdef ENABLE_LOGS_PREVIEW
 
 #  include <memory>
+#  include <vector>
 
-#  include "opentelemetry/sdk/logs/logger_context.h"
-#  include "opentelemetry/sdk/logs/processor.h"
-#  include "opentelemetry/sdk/resource/resource.h"
 #  include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
 {
+namespace resource
+{
+class Resource;
+}  // namespace resource
+
 namespace logs
 {
+class LoggerContext;
+class LogRecordProcessor;
 
 /**
  * Factory class for LoggerContext.
diff --git a/sdk/include/opentelemetry/sdk/logs/logger_provider.h b/sdk/include/opentelemetry/sdk/logs/logger_provider.h
index a5190c7a30..3c9211cc36 100644
--- a/sdk/include/opentelemetry/sdk/logs/logger_provider.h
+++ b/sdk/include/opentelemetry/sdk/logs/logger_provider.h
@@ -6,16 +6,13 @@
 
 #  include <memory>
 #  include <mutex>
-#  include <string>
 #  include <vector>
 
 #  include "opentelemetry/logs/logger_provider.h"
-#  include "opentelemetry/logs/noop.h"
 #  include "opentelemetry/nostd/shared_ptr.h"
-#  include "opentelemetry/sdk/common/atomic_shared_ptr.h"
-#  include "opentelemetry/sdk/logs/logger.h"
-#  include "opentelemetry/sdk/logs/logger_context.h"
-#  include "opentelemetry/sdk/logs/processor.h"
+#  include "opentelemetry/nostd/string_view.h"
+#  include "opentelemetry/sdk/resource/resource.h"
+#  include "opentelemetry/version.h"
 
 // Define the maximum number of loggers that are allowed to be registered to the loggerprovider.
 // TODO: Add link to logging spec once this is added to it
@@ -27,6 +24,8 @@ namespace sdk
 namespace logs
 {
 class Logger;
+class LoggerContext;
+class LogRecordProcessor;
 
 class LoggerProvider final : public opentelemetry::logs::LoggerProvider
 {
diff --git a/sdk/include/opentelemetry/sdk/logs/logger_provider_factory.h b/sdk/include/opentelemetry/sdk/logs/logger_provider_factory.h
index 0795129df3..bbd715dc89 100644
--- a/sdk/include/opentelemetry/sdk/logs/logger_provider_factory.h
+++ b/sdk/include/opentelemetry/sdk/logs/logger_provider_factory.h
@@ -8,18 +8,25 @@
 #  include <memory>
 #  include <vector>
 
-#  include "opentelemetry/logs/logger_provider.h"
-#  include "opentelemetry/nostd/shared_ptr.h"
-#  include "opentelemetry/sdk/common/atomic_shared_ptr.h"
-#  include "opentelemetry/sdk/logs/logger.h"
-#  include "opentelemetry/sdk/logs/logger_context.h"
-#  include "opentelemetry/sdk/logs/processor.h"
+#  include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
+namespace logs
+{
+class LoggerProvider;
+}  // namespace logs
+
 namespace sdk
 {
+namespace resource
+{
+class Resource;
+}  // namespace resource
+
 namespace logs
 {
+class LoggerContext;
+class LogRecordProcessor;
 
 /**
  * Factory class for LoggerProvider.
diff --git a/sdk/include/opentelemetry/sdk/logs/multi_log_record_processor.h b/sdk/include/opentelemetry/sdk/logs/multi_log_record_processor.h
index 54a7e7959e..91995aa6a3 100644
--- a/sdk/include/opentelemetry/sdk/logs/multi_log_record_processor.h
+++ b/sdk/include/opentelemetry/sdk/logs/multi_log_record_processor.h
@@ -5,12 +5,11 @@
 
 #ifdef ENABLE_LOGS_PREVIEW
 
+#  include <chrono>
 #  include <memory>
 #  include <vector>
 
-#  include "opentelemetry/sdk/logs/multi_recordable.h"
 #  include "opentelemetry/sdk/logs/processor.h"
-#  include "opentelemetry/sdk/resource/resource.h"
 #  include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
@@ -18,6 +17,7 @@ namespace sdk
 {
 namespace logs
 {
+class Recordable;
 
 /**
  * Log processor allow hooks for receive method invocations.
diff --git a/sdk/include/opentelemetry/sdk/logs/multi_log_record_processor_factory.h b/sdk/include/opentelemetry/sdk/logs/multi_log_record_processor_factory.h
index c91cad52ff..c3e87c12db 100644
--- a/sdk/include/opentelemetry/sdk/logs/multi_log_record_processor_factory.h
+++ b/sdk/include/opentelemetry/sdk/logs/multi_log_record_processor_factory.h
@@ -8,13 +8,14 @@
 #  include <memory>
 #  include <vector>
 
-#  include "opentelemetry/sdk/logs/processor.h"
+#  include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
 {
 namespace logs
 {
+class LogRecordProcessor;
 
 /**
  * Factory class for MultiLogRecordProcessor.
diff --git a/sdk/include/opentelemetry/sdk/logs/multi_recordable.h b/sdk/include/opentelemetry/sdk/logs/multi_recordable.h
index 5944d49b39..97ae1451fc 100644
--- a/sdk/include/opentelemetry/sdk/logs/multi_recordable.h
+++ b/sdk/include/opentelemetry/sdk/logs/multi_recordable.h
@@ -10,7 +10,6 @@
 #  include <unordered_map>
 
 #  include "opentelemetry/common/macros.h"
-#  include "opentelemetry/sdk/logs/processor.h"
 #  include "opentelemetry/sdk/logs/recordable.h"
 #  include "opentelemetry/sdk/resource/resource.h"
 #  include "opentelemetry/version.h"
@@ -20,6 +19,8 @@ namespace sdk
 {
 namespace logs
 {
+class LogRecordProcessor;
+
 class MultiRecordable final : public Recordable
 {
 public:
diff --git a/sdk/include/opentelemetry/sdk/logs/processor.h b/sdk/include/opentelemetry/sdk/logs/processor.h
index 97f823a25b..8a409e0020 100644
--- a/sdk/include/opentelemetry/sdk/logs/processor.h
+++ b/sdk/include/opentelemetry/sdk/logs/processor.h
@@ -7,14 +7,15 @@
 #  include <chrono>
 #  include <memory>
 
-#  include "opentelemetry/nostd/unique_ptr.h"
-#  include "opentelemetry/sdk/logs/recordable.h"
+#  include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
 {
 namespace logs
 {
+class Recordable;
+
 /**
  * The Log Processor is responsible for passing log records
  * to the configured exporter.
diff --git a/sdk/include/opentelemetry/sdk/logs/read_write_log_record.h b/sdk/include/opentelemetry/sdk/logs/read_write_log_record.h
index a850072134..915c8852e9 100644
--- a/sdk/include/opentelemetry/sdk/logs/read_write_log_record.h
+++ b/sdk/include/opentelemetry/sdk/logs/read_write_log_record.h
@@ -6,18 +6,17 @@
 
 #  include <memory>
 #  include <string>
+#  include <unordered_map>
 
 #  include "opentelemetry/common/attribute_value.h"
 #  include "opentelemetry/common/key_value_iterable.h"
 #  include "opentelemetry/common/timestamp.h"
 #  include "opentelemetry/logs/log_record.h"
 #  include "opentelemetry/logs/severity.h"
-#  include "opentelemetry/nostd/unique_ptr.h"
+#  include "opentelemetry/nostd/string_view.h"
 #  include "opentelemetry/sdk/common/attribute_utils.h"
 #  include "opentelemetry/sdk/common/empty_attributes.h"
-#  include "opentelemetry/sdk/instrumentationscope/instrumentation_scope.h"
 #  include "opentelemetry/sdk/logs/readable_log_record.h"
-#  include "opentelemetry/sdk/resource/resource.h"
 #  include "opentelemetry/trace/span_id.h"
 #  include "opentelemetry/trace/trace_flags.h"
 #  include "opentelemetry/trace/trace_id.h"
diff --git a/sdk/include/opentelemetry/sdk/logs/readable_log_record.h b/sdk/include/opentelemetry/sdk/logs/readable_log_record.h
index 90a1c4b7b7..ba20ca7949 100644
--- a/sdk/include/opentelemetry/sdk/logs/readable_log_record.h
+++ b/sdk/include/opentelemetry/sdk/logs/readable_log_record.h
@@ -8,22 +8,32 @@
 #  include <unordered_map>
 
 #  include "opentelemetry/common/attribute_value.h"
-#  include "opentelemetry/common/key_value_iterable.h"
 #  include "opentelemetry/common/timestamp.h"
 #  include "opentelemetry/logs/severity.h"
-#  include "opentelemetry/sdk/common/attribute_utils.h"
-#  include "opentelemetry/sdk/common/empty_attributes.h"
-#  include "opentelemetry/sdk/instrumentationscope/instrumentation_scope.h"
+#  include "opentelemetry/nostd/string_view.h"
 #  include "opentelemetry/sdk/logs/recordable.h"
-#  include "opentelemetry/sdk/resource/resource.h"
-#  include "opentelemetry/trace/span_id.h"
-#  include "opentelemetry/trace/trace_flags.h"
-#  include "opentelemetry/trace/trace_id.h"
 #  include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
+namespace trace
+{
+class SpanId;
+class TraceId;
+class TraceFlags;
+}  // namespace trace
+
 namespace sdk
 {
+namespace resource
+{
+class Resource;
+}  // namespace resource
+
+namespace instrumentationscope
+{
+class InstrumentationScope;
+}  // namespace instrumentationscope
+
 namespace logs
 {
 /**
diff --git a/sdk/include/opentelemetry/sdk/logs/recordable.h b/sdk/include/opentelemetry/sdk/logs/recordable.h
index 983a2e6b57..ff0099af56 100644
--- a/sdk/include/opentelemetry/sdk/logs/recordable.h
+++ b/sdk/include/opentelemetry/sdk/logs/recordable.h
@@ -4,24 +4,22 @@
 #pragma once
 #ifdef ENABLE_LOGS_PREVIEW
 
-#  include "opentelemetry/common/attribute_value.h"
-#  include "opentelemetry/common/key_value_iterable.h"
-#  include "opentelemetry/common/timestamp.h"
 #  include "opentelemetry/logs/log_record.h"
-#  include "opentelemetry/logs/severity.h"
-#  include "opentelemetry/sdk/common/attribute_utils.h"
-#  include "opentelemetry/sdk/common/empty_attributes.h"
-#  include "opentelemetry/sdk/instrumentationscope/instrumentation_scope.h"
-#  include "opentelemetry/sdk/logs/recordable.h"
-#  include "opentelemetry/sdk/resource/resource.h"
-#  include "opentelemetry/trace/span_id.h"
-#  include "opentelemetry/trace/trace_flags.h"
-#  include "opentelemetry/trace/trace_id.h"
 #  include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
 {
+namespace resource
+{
+class Resource;
+}  // namespace resource
+
+namespace instrumentationscope
+{
+class InstrumentationScope;
+}  // namespace instrumentationscope
+
 namespace logs
 {
 /**
diff --git a/sdk/include/opentelemetry/sdk/logs/simple_log_record_processor.h b/sdk/include/opentelemetry/sdk/logs/simple_log_record_processor.h
index f3d6bc27c3..4bb3dab2de 100644
--- a/sdk/include/opentelemetry/sdk/logs/simple_log_record_processor.h
+++ b/sdk/include/opentelemetry/sdk/logs/simple_log_record_processor.h
@@ -5,18 +5,21 @@
 #ifdef ENABLE_LOGS_PREVIEW
 
 #  include <atomic>
+#  include <chrono>
 #  include <memory>
-#  include <mutex>
 
 #  include "opentelemetry/common/spin_lock_mutex.h"
-#  include "opentelemetry/sdk/logs/exporter.h"
 #  include "opentelemetry/sdk/logs/processor.h"
+#  include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
 {
 namespace logs
 {
+class LogRecordExporter;
+class Recordable;
+
 /**
  * The simple log processor passes all log records
  * in a batch of 1 to the configured
diff --git a/sdk/include/opentelemetry/sdk/logs/simple_log_record_processor_factory.h b/sdk/include/opentelemetry/sdk/logs/simple_log_record_processor_factory.h
index aec65349c5..cd022aadd6 100644
--- a/sdk/include/opentelemetry/sdk/logs/simple_log_record_processor_factory.h
+++ b/sdk/include/opentelemetry/sdk/logs/simple_log_record_processor_factory.h
@@ -7,14 +7,15 @@
 
 #  include <memory>
 
-#  include "opentelemetry/sdk/logs/exporter.h"
-#  include "opentelemetry/sdk/logs/processor.h"
+#  include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
 {
 namespace logs
 {
+class LogRecordExporter;
+class LogRecordProcessor;
 
 /**
  * Factory class for SimpleLogRecordProcessor.
diff --git a/sdk/include/opentelemetry/sdk/metrics/aggregation/aggregation.h b/sdk/include/opentelemetry/sdk/metrics/aggregation/aggregation.h
index 361a1cd3b8..a4ec9175c5 100644
--- a/sdk/include/opentelemetry/sdk/metrics/aggregation/aggregation.h
+++ b/sdk/include/opentelemetry/sdk/metrics/aggregation/aggregation.h
@@ -3,9 +3,11 @@
 
 #pragma once
 
-#include "opentelemetry/nostd/string_view.h"
+#include <memory>
+
 #include "opentelemetry/sdk/metrics/data/metric_data.h"
-#include "opentelemetry/sdk/metrics/data/point_data.h"
+#include "opentelemetry/version.h"
+
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
 {
diff --git a/sdk/include/opentelemetry/sdk/metrics/aggregation/aggregation_config.h b/sdk/include/opentelemetry/sdk/metrics/aggregation/aggregation_config.h
index 69dc4c8864..f5a48d7ddb 100644
--- a/sdk/include/opentelemetry/sdk/metrics/aggregation/aggregation_config.h
+++ b/sdk/include/opentelemetry/sdk/metrics/aggregation/aggregation_config.h
@@ -3,10 +3,10 @@
 
 #pragma once
 
-#include "opentelemetry/version.h"
-
 #include <vector>
 
+#include "opentelemetry/version.h"
+
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
 {
diff --git a/sdk/include/opentelemetry/sdk/metrics/aggregation/default_aggregation.h b/sdk/include/opentelemetry/sdk/metrics/aggregation/default_aggregation.h
index 927c17e968..203a2d32b9 100644
--- a/sdk/include/opentelemetry/sdk/metrics/aggregation/default_aggregation.h
+++ b/sdk/include/opentelemetry/sdk/metrics/aggregation/default_aggregation.h
@@ -4,23 +4,22 @@
 #pragma once
 
 #include <memory>
-#include "opentelemetry/common/spin_lock_mutex.h"
+
 #include "opentelemetry/sdk/metrics/aggregation/aggregation.h"
-#include "opentelemetry/sdk/metrics/aggregation/aggregation_config.h"
 #include "opentelemetry/sdk/metrics/aggregation/drop_aggregation.h"
 #include "opentelemetry/sdk/metrics/aggregation/histogram_aggregation.h"
 #include "opentelemetry/sdk/metrics/aggregation/lastvalue_aggregation.h"
 #include "opentelemetry/sdk/metrics/aggregation/sum_aggregation.h"
 #include "opentelemetry/sdk/metrics/data/point_data.h"
 #include "opentelemetry/sdk/metrics/instruments.h"
-
-#include <mutex>
+#include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
 {
 namespace metrics
 {
+class AggregationConfig;
 
 class DefaultAggregation
 {
diff --git a/sdk/include/opentelemetry/sdk/metrics/aggregation/drop_aggregation.h b/sdk/include/opentelemetry/sdk/metrics/aggregation/drop_aggregation.h
index 713ce60b8e..4664f8dcd4 100644
--- a/sdk/include/opentelemetry/sdk/metrics/aggregation/drop_aggregation.h
+++ b/sdk/include/opentelemetry/sdk/metrics/aggregation/drop_aggregation.h
@@ -3,10 +3,11 @@
 
 #pragma once
 
-#include "opentelemetry/common/spin_lock_mutex.h"
-#include "opentelemetry/sdk/metrics/aggregation/aggregation.h"
+#include <memory>
 
-#include <mutex>
+#include "opentelemetry/sdk/metrics/aggregation/aggregation.h"
+#include "opentelemetry/sdk/metrics/data/point_data.h"
+#include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
diff --git a/sdk/include/opentelemetry/sdk/metrics/aggregation/histogram_aggregation.h b/sdk/include/opentelemetry/sdk/metrics/aggregation/histogram_aggregation.h
index 5d1097d93f..4419ee81f3 100644
--- a/sdk/include/opentelemetry/sdk/metrics/aggregation/histogram_aggregation.h
+++ b/sdk/include/opentelemetry/sdk/metrics/aggregation/histogram_aggregation.h
@@ -3,18 +3,20 @@
 
 #pragma once
 
+#include <algorithm>
 #include <memory>
+
 #include "opentelemetry/common/spin_lock_mutex.h"
 #include "opentelemetry/sdk/metrics/aggregation/aggregation.h"
-#include "opentelemetry/sdk/metrics/aggregation/aggregation_config.h"
-
-#include <mutex>
+#include "opentelemetry/sdk/metrics/data/point_data.h"
+#include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
 {
 namespace metrics
 {
+class AggregationConfig;
 
 class LongHistogramAggregation : public Aggregation
 {
diff --git a/sdk/include/opentelemetry/sdk/metrics/aggregation/lastvalue_aggregation.h b/sdk/include/opentelemetry/sdk/metrics/aggregation/lastvalue_aggregation.h
index 05242e304d..859fe26d6b 100644
--- a/sdk/include/opentelemetry/sdk/metrics/aggregation/lastvalue_aggregation.h
+++ b/sdk/include/opentelemetry/sdk/metrics/aggregation/lastvalue_aggregation.h
@@ -3,10 +3,12 @@
 
 #pragma once
 
+#include <memory>
+
 #include "opentelemetry/common/spin_lock_mutex.h"
 #include "opentelemetry/sdk/metrics/aggregation/aggregation.h"
-
-#include <mutex>
+#include "opentelemetry/sdk/metrics/data/point_data.h"
+#include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
diff --git a/sdk/include/opentelemetry/sdk/metrics/aggregation/sum_aggregation.h b/sdk/include/opentelemetry/sdk/metrics/aggregation/sum_aggregation.h
index 881854e0c2..a098d86b72 100644
--- a/sdk/include/opentelemetry/sdk/metrics/aggregation/sum_aggregation.h
+++ b/sdk/include/opentelemetry/sdk/metrics/aggregation/sum_aggregation.h
@@ -3,10 +3,12 @@
 
 #pragma once
 
+#include <memory>
+
 #include "opentelemetry/common/spin_lock_mutex.h"
 #include "opentelemetry/sdk/metrics/aggregation/aggregation.h"
-
-#include <mutex>
+#include "opentelemetry/sdk/metrics/data/point_data.h"
+#include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
diff --git a/sdk/include/opentelemetry/sdk/metrics/async_instruments.h b/sdk/include/opentelemetry/sdk/metrics/async_instruments.h
index 321c8089c1..a22ce1f0f8 100644
--- a/sdk/include/opentelemetry/sdk/metrics/async_instruments.h
+++ b/sdk/include/opentelemetry/sdk/metrics/async_instruments.h
@@ -3,11 +3,12 @@
 
 #pragma once
 
+#include <memory>
+
 #include "opentelemetry/metrics/async_instruments.h"
 #include "opentelemetry/metrics/observer_result.h"
-#include "opentelemetry/nostd/string_view.h"
 #include "opentelemetry/sdk/metrics/instruments.h"
-#include "opentelemetry/sdk/metrics/state/observable_registry.h"
+#include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
@@ -16,6 +17,7 @@ namespace metrics
 {
 
 class AsyncWritableMetricStorage;
+class ObservableRegistry;
 
 class ObservableInstrument : public opentelemetry::metrics::ObservableInstrument
 {
diff --git a/sdk/include/opentelemetry/sdk/metrics/data/exemplar_data.h b/sdk/include/opentelemetry/sdk/metrics/data/exemplar_data.h
index b9f72e9b58..0420b50aab 100644
--- a/sdk/include/opentelemetry/sdk/metrics/data/exemplar_data.h
+++ b/sdk/include/opentelemetry/sdk/metrics/data/exemplar_data.h
@@ -6,11 +6,10 @@
 #include <memory>
 
 #include "opentelemetry/common/timestamp.h"
-#include "opentelemetry/context/context.h"
 #include "opentelemetry/sdk/common/attribute_utils.h"
 #include "opentelemetry/sdk/metrics/data/metric_data.h"
-#include "opentelemetry/sdk/metrics/export/metric_producer.h"
 #include "opentelemetry/trace/span_context.h"
+#include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
diff --git a/sdk/include/opentelemetry/sdk/metrics/data/metric_data.h b/sdk/include/opentelemetry/sdk/metrics/data/metric_data.h
index 28a53dd407..ad1084f581 100644
--- a/sdk/include/opentelemetry/sdk/metrics/data/metric_data.h
+++ b/sdk/include/opentelemetry/sdk/metrics/data/metric_data.h
@@ -3,12 +3,12 @@
 
 #pragma once
 
+#include <vector>
+
 #include "opentelemetry/nostd/variant.h"
 #include "opentelemetry/sdk/common/attribute_utils.h"
-#include "opentelemetry/sdk/instrumentationscope/instrumentation_scope.h"
 #include "opentelemetry/sdk/metrics/data/point_data.h"
 #include "opentelemetry/sdk/metrics/instruments.h"
-#include "opentelemetry/sdk/resource/resource.h"
 #include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
diff --git a/sdk/include/opentelemetry/sdk/metrics/data/point_data.h b/sdk/include/opentelemetry/sdk/metrics/data/point_data.h
index 62ba3df1bc..9bf82e040a 100644
--- a/sdk/include/opentelemetry/sdk/metrics/data/point_data.h
+++ b/sdk/include/opentelemetry/sdk/metrics/data/point_data.h
@@ -3,13 +3,12 @@
 
 #pragma once
 
+#include <vector>
+
 #include "opentelemetry/common/timestamp.h"
 #include "opentelemetry/nostd/variant.h"
-#include "opentelemetry/sdk/metrics/instruments.h"
 #include "opentelemetry/version.h"
 
-#include <vector>
-
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
 {
diff --git a/sdk/include/opentelemetry/sdk/metrics/exemplar/always_sample_filter.h b/sdk/include/opentelemetry/sdk/metrics/exemplar/always_sample_filter.h
index c10ec061bb..4a1366aa80 100644
--- a/sdk/include/opentelemetry/sdk/metrics/exemplar/always_sample_filter.h
+++ b/sdk/include/opentelemetry/sdk/metrics/exemplar/always_sample_filter.h
@@ -4,8 +4,14 @@
 #pragma once
 
 #include "opentelemetry/sdk/metrics/exemplar/filter.h"
+#include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
+namespace context
+{
+class Context;
+}  // namespace context
+
 namespace sdk
 {
 namespace metrics
diff --git a/sdk/include/opentelemetry/sdk/metrics/exemplar/filter.h b/sdk/include/opentelemetry/sdk/metrics/exemplar/filter.h
index cfc3439992..f3bc904e26 100644
--- a/sdk/include/opentelemetry/sdk/metrics/exemplar/filter.h
+++ b/sdk/include/opentelemetry/sdk/metrics/exemplar/filter.h
@@ -3,12 +3,24 @@
 
 #pragma once
 
-#include "opentelemetry/context/context.h"
+#include <memory>
+
 #include "opentelemetry/sdk/common/attribute_utils.h"
+#include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
+namespace context
+{
+class Context;
+}  // namespace context
+
 namespace sdk
 {
+namespace common
+{
+class OrderedAttributeMap;
+}  // namespace common
+
 namespace metrics
 {
 using MetricAttributes = opentelemetry::sdk::common::OrderedAttributeMap;
diff --git a/sdk/include/opentelemetry/sdk/metrics/exemplar/filtered_exemplar_reservoir.h b/sdk/include/opentelemetry/sdk/metrics/exemplar/filtered_exemplar_reservoir.h
index 5264c33170..6ed97a689e 100644
--- a/sdk/include/opentelemetry/sdk/metrics/exemplar/filtered_exemplar_reservoir.h
+++ b/sdk/include/opentelemetry/sdk/metrics/exemplar/filtered_exemplar_reservoir.h
@@ -5,13 +5,22 @@
 
 #include <memory>
 #include <vector>
-#include "opentelemetry/context/context.h"
-#include "opentelemetry/nostd/shared_ptr.h"
-#include "opentelemetry/sdk/common/attribute_utils.h"
+
 #include "opentelemetry/sdk/metrics/exemplar/filter.h"
 #include "opentelemetry/sdk/metrics/exemplar/reservoir.h"
+#include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
+namespace common
+{
+class SystemTimestamp;
+}  // namespace common
+
+namespace context
+{
+class Context;
+}  // namespace context
+
 namespace sdk
 {
 namespace metrics
diff --git a/sdk/include/opentelemetry/sdk/metrics/exemplar/fixed_size_exemplar_reservoir.h b/sdk/include/opentelemetry/sdk/metrics/exemplar/fixed_size_exemplar_reservoir.h
index d2cc13f20c..76f5742ca2 100644
--- a/sdk/include/opentelemetry/sdk/metrics/exemplar/fixed_size_exemplar_reservoir.h
+++ b/sdk/include/opentelemetry/sdk/metrics/exemplar/fixed_size_exemplar_reservoir.h
@@ -5,6 +5,7 @@
 
 #include <memory>
 #include <vector>
+
 #include "opentelemetry/context/context.h"
 #include "opentelemetry/nostd/function_ref.h"
 #include "opentelemetry/nostd/shared_ptr.h"
diff --git a/sdk/include/opentelemetry/sdk/metrics/exemplar/histogram_exemplar_reservoir.h b/sdk/include/opentelemetry/sdk/metrics/exemplar/histogram_exemplar_reservoir.h
index 7da7dc8ac0..bbc032df3b 100644
--- a/sdk/include/opentelemetry/sdk/metrics/exemplar/histogram_exemplar_reservoir.h
+++ b/sdk/include/opentelemetry/sdk/metrics/exemplar/histogram_exemplar_reservoir.h
@@ -5,16 +5,25 @@
 
 #include <memory>
 #include <vector>
-#include "opentelemetry/context/context.h"
-#include "opentelemetry/nostd/shared_ptr.h"
-#include "opentelemetry/sdk/common/attribute_utils.h"
+
 #include "opentelemetry/sdk/metrics/data/exemplar_data.h"
 #include "opentelemetry/sdk/metrics/exemplar/filter.h"
 #include "opentelemetry/sdk/metrics/exemplar/fixed_size_exemplar_reservoir.h"
 #include "opentelemetry/sdk/metrics/exemplar/reservoir.h"
 #include "opentelemetry/sdk/metrics/exemplar/reservoir_cell_selector.h"
+#include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
+namespace common
+{
+class OrderedAttributeMap;
+}  // namespace common
+
+namespace context
+{
+class Context;
+}  // namespace context
+
 namespace sdk
 {
 namespace metrics
diff --git a/sdk/include/opentelemetry/sdk/metrics/exemplar/never_sample_filter.h b/sdk/include/opentelemetry/sdk/metrics/exemplar/never_sample_filter.h
index 1f2967467b..84d4ef9f77 100644
--- a/sdk/include/opentelemetry/sdk/metrics/exemplar/never_sample_filter.h
+++ b/sdk/include/opentelemetry/sdk/metrics/exemplar/never_sample_filter.h
@@ -4,8 +4,14 @@
 #pragma once
 
 #include "opentelemetry/sdk/metrics/exemplar/filter.h"
+#include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
+namespace context
+{
+class Context;
+}  // namespace context
+
 namespace sdk
 {
 namespace metrics
diff --git a/sdk/include/opentelemetry/sdk/metrics/exemplar/no_exemplar_reservoir.h b/sdk/include/opentelemetry/sdk/metrics/exemplar/no_exemplar_reservoir.h
index d137991f71..edcde3c12f 100644
--- a/sdk/include/opentelemetry/sdk/metrics/exemplar/no_exemplar_reservoir.h
+++ b/sdk/include/opentelemetry/sdk/metrics/exemplar/no_exemplar_reservoir.h
@@ -3,17 +3,30 @@
 
 #pragma once
 
+#include <memory>
 #include <vector>
-#include "opentelemetry/context/context.h"
-#include "opentelemetry/nostd/shared_ptr.h"
-#include "opentelemetry/sdk/common/attribute_utils.h"
+
+#include "opentelemetry/sdk/metrics/exemplar/filter.h"
 #include "opentelemetry/sdk/metrics/exemplar/reservoir.h"
+#include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
+namespace common
+{
+class SystemTimestamp;
+}  // namespace common
+
+namespace context
+{
+class Context;
+}  // namespace context
+
 namespace sdk
 {
 namespace metrics
 {
+class ExemplarData;
+
 class NoExemplarReservoir final : public ExemplarReservoir
 {
 
diff --git a/sdk/include/opentelemetry/sdk/metrics/exemplar/reservoir.h b/sdk/include/opentelemetry/sdk/metrics/exemplar/reservoir.h
index ea418b698d..258e099f0f 100644
--- a/sdk/include/opentelemetry/sdk/metrics/exemplar/reservoir.h
+++ b/sdk/include/opentelemetry/sdk/metrics/exemplar/reservoir.h
@@ -3,16 +3,30 @@
 
 #pragma once
 
+#include <memory>
 #include <vector>
-#include "opentelemetry/sdk/metrics/data/exemplar_data.h"
+
 #include "opentelemetry/sdk/metrics/exemplar/filter.h"
 #include "opentelemetry/sdk/metrics/exemplar/reservoir_cell_selector.h"
+#include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
+namespace common
+{
+class SystemTimestamp;
+}  // namespace common
+
+namespace context
+{
+class Context;
+}  // namespace context
+
 namespace sdk
 {
 namespace metrics
 {
+class ExemplarData;
+
 /**
  * An interface for an exemplar reservoir of samples.
  *
diff --git a/sdk/include/opentelemetry/sdk/metrics/exemplar/reservoir_cell.h b/sdk/include/opentelemetry/sdk/metrics/exemplar/reservoir_cell.h
index 2309fc72e4..6074393d2d 100644
--- a/sdk/include/opentelemetry/sdk/metrics/exemplar/reservoir_cell.h
+++ b/sdk/include/opentelemetry/sdk/metrics/exemplar/reservoir_cell.h
@@ -5,16 +5,20 @@
 
 #include <cstddef>
 #include <memory>
-#include <vector>
+
 #include "opentelemetry/common/timestamp.h"
-#include "opentelemetry/context/context.h"
-#include "opentelemetry/nostd/shared_ptr.h"
-#include "opentelemetry/sdk/common/attribute_utils.h"
+#include "opentelemetry/nostd/variant.h"
 #include "opentelemetry/sdk/metrics/data/exemplar_data.h"
 #include "opentelemetry/sdk/metrics/exemplar/filter.h"
 #include "opentelemetry/trace/context.h"
+#include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
+namespace context
+{
+class Context;
+}  // namespace context
+
 namespace sdk
 {
 namespace metrics
diff --git a/sdk/include/opentelemetry/sdk/metrics/exemplar/reservoir_cell_selector.h b/sdk/include/opentelemetry/sdk/metrics/exemplar/reservoir_cell_selector.h
index 1017d64aa7..b3b2f09e23 100644
--- a/sdk/include/opentelemetry/sdk/metrics/exemplar/reservoir_cell_selector.h
+++ b/sdk/include/opentelemetry/sdk/metrics/exemplar/reservoir_cell_selector.h
@@ -4,14 +4,18 @@
 #pragma once
 
 #include <cstddef>
-#include <memory>
 #include <vector>
-#include "opentelemetry/context/context.h"
-#include "opentelemetry/nostd/shared_ptr.h"
-#include "opentelemetry/sdk/common/attribute_utils.h"
+
+#include "opentelemetry/sdk/metrics/exemplar/filter.h"
 #include "opentelemetry/sdk/metrics/exemplar/reservoir_cell.h"
+#include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
+namespace context
+{
+class Context;
+}  // namespace context
+
 namespace sdk
 {
 namespace metrics
diff --git a/sdk/include/opentelemetry/sdk/metrics/exemplar/with_trace_sample_filter.h b/sdk/include/opentelemetry/sdk/metrics/exemplar/with_trace_sample_filter.h
index de01cbc632..fbc0489d3d 100644
--- a/sdk/include/opentelemetry/sdk/metrics/exemplar/with_trace_sample_filter.h
+++ b/sdk/include/opentelemetry/sdk/metrics/exemplar/with_trace_sample_filter.h
@@ -5,6 +5,7 @@
 
 #include "opentelemetry/sdk/metrics/exemplar/filter.h"
 #include "opentelemetry/trace/context.h"
+#include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
diff --git a/sdk/include/opentelemetry/sdk/metrics/export/metric_producer.h b/sdk/include/opentelemetry/sdk/metrics/export/metric_producer.h
index 82b8c1c474..2a0c87fcaa 100644
--- a/sdk/include/opentelemetry/sdk/metrics/export/metric_producer.h
+++ b/sdk/include/opentelemetry/sdk/metrics/export/metric_producer.h
@@ -3,13 +3,25 @@
 
 #pragma once
 
-#include "opentelemetry/sdk/instrumentationscope/instrumentation_scope.h"
+#include <vector>
+
+#include "opentelemetry/nostd/function_ref.h"
 #include "opentelemetry/sdk/metrics/data/metric_data.h"
-#include "opentelemetry/sdk/resource/resource.h"
+#include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
 {
+namespace resource
+{
+class Resource;
+}  // namespace resource
+
+namespace instrumentationscope
+{
+class InstrumentationScope;
+}  // namespace instrumentationscope
+
 namespace metrics
 {
 
diff --git a/sdk/include/opentelemetry/sdk/metrics/export/periodic_exporting_metric_reader.h b/sdk/include/opentelemetry/sdk/metrics/export/periodic_exporting_metric_reader.h
index 83773ffb61..29c2e351e5 100644
--- a/sdk/include/opentelemetry/sdk/metrics/export/periodic_exporting_metric_reader.h
+++ b/sdk/include/opentelemetry/sdk/metrics/export/periodic_exporting_metric_reader.h
@@ -3,14 +3,16 @@
 
 #pragma once
 
-#include "opentelemetry/sdk/metrics/metric_reader.h"
-#include "opentelemetry/version.h"
-
 #include <atomic>
 #include <chrono>
 #include <condition_variable>
+#include <memory>
+#include <mutex>
 #include <thread>
 
+#include "opentelemetry/sdk/metrics/metric_reader.h"
+#include "opentelemetry/version.h"
+
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
 {
diff --git a/sdk/include/opentelemetry/sdk/metrics/instrument_metadata_validator.h b/sdk/include/opentelemetry/sdk/metrics/instrument_metadata_validator.h
index 95848a8eec..fec1027746 100644
--- a/sdk/include/opentelemetry/sdk/metrics/instrument_metadata_validator.h
+++ b/sdk/include/opentelemetry/sdk/metrics/instrument_metadata_validator.h
@@ -4,6 +4,7 @@
 #pragma once
 
 #include <string>
+
 #include "opentelemetry/common/macros.h"
 #include "opentelemetry/nostd/string_view.h"
 #include "opentelemetry/version.h"
diff --git a/sdk/include/opentelemetry/sdk/metrics/instruments.h b/sdk/include/opentelemetry/sdk/metrics/instruments.h
index 6c6497555b..84244128a4 100644
--- a/sdk/include/opentelemetry/sdk/metrics/instruments.h
+++ b/sdk/include/opentelemetry/sdk/metrics/instruments.h
@@ -4,8 +4,10 @@
 #pragma once
 
 #include <functional>
-#include "opentelemetry/common/macros.h"
+#include <string>
+
 #include "opentelemetry/sdk/common/attribute_utils.h"
+#include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
diff --git a/sdk/include/opentelemetry/sdk/metrics/meter.h b/sdk/include/opentelemetry/sdk/metrics/meter.h
index 6beff61063..41a10f69e9 100644
--- a/sdk/include/opentelemetry/sdk/metrics/meter.h
+++ b/sdk/include/opentelemetry/sdk/metrics/meter.h
@@ -4,15 +4,22 @@
 #pragma once
 
 #include <chrono>
+#include <memory>
+#include <string>
+#include <unordered_map>
+#include <vector>
+
+#include "opentelemetry/common/macros.h"
 #include "opentelemetry/metrics/meter.h"
 #include "opentelemetry/metrics/noop.h"
+#include "opentelemetry/nostd/shared_ptr.h"
+#include "opentelemetry/nostd/string_view.h"
+#include "opentelemetry/nostd/unique_ptr.h"
 #include "opentelemetry/sdk/instrumentationscope/instrumentation_scope.h"
 #include "opentelemetry/sdk/metrics/instrument_metadata_validator.h"
 #include "opentelemetry/sdk/metrics/instruments.h"
 #include "opentelemetry/sdk/metrics/meter_context.h"
 #include "opentelemetry/sdk/metrics/state/async_metric_storage.h"
-
-#include "opentelemetry/common/macros.h"
 #include "opentelemetry/sdk/resource/resource.h"
 #include "opentelemetry/sdk_config.h"
 #include "opentelemetry/version.h"
diff --git a/sdk/include/opentelemetry/sdk/metrics/meter_context.h b/sdk/include/opentelemetry/sdk/metrics/meter_context.h
index 75ab2a4be9..8155b4da9f 100644
--- a/sdk/include/opentelemetry/sdk/metrics/meter_context.h
+++ b/sdk/include/opentelemetry/sdk/metrics/meter_context.h
@@ -3,18 +3,19 @@
 
 #pragma once
 
+#include <atomic>
+#include <chrono>
+#include <memory>
+#include <vector>
+
 #include "opentelemetry/common/spin_lock_mutex.h"
-#include "opentelemetry/sdk/metrics/state/metric_collector.h"
-#include "opentelemetry/sdk/metrics/view/instrument_selector.h"
-#include "opentelemetry/sdk/metrics/view/meter_selector.h"
+#include "opentelemetry/common/timestamp.h"
+#include "opentelemetry/nostd/function_ref.h"
+#include "opentelemetry/nostd/span.h"
 #include "opentelemetry/sdk/metrics/view/view_registry.h"
 #include "opentelemetry/sdk/resource/resource.h"
 #include "opentelemetry/version.h"
 
-#include <chrono>
-#include <memory>
-#include <vector>
-
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
 {
@@ -22,8 +23,11 @@ namespace metrics
 {
 
 // forward declaration
+class CollectorHandle;
+class InstrumentSelector;
 class Meter;
 class MetricReader;
+class MeterSelector;
 
 /**
  * A class which stores the MeterProvider context.
diff --git a/sdk/include/opentelemetry/sdk/metrics/meter_provider.h b/sdk/include/opentelemetry/sdk/metrics/meter_provider.h
index f2c72e2d25..fedf6aac61 100644
--- a/sdk/include/opentelemetry/sdk/metrics/meter_provider.h
+++ b/sdk/include/opentelemetry/sdk/metrics/meter_provider.h
@@ -3,24 +3,30 @@
 
 #pragma once
 
+#include <chrono>
 #include <memory>
 #include <mutex>
-#include <vector>
-#include "opentelemetry/metrics/meter.h"
+
 #include "opentelemetry/metrics/meter_provider.h"
 #include "opentelemetry/nostd/shared_ptr.h"
-#include "opentelemetry/sdk/metrics/meter.h"
-#include "opentelemetry/sdk/metrics/meter_context.h"
+#include "opentelemetry/nostd/string_view.h"
+#include "opentelemetry/sdk/metrics/view/view_registry.h"
 #include "opentelemetry/sdk/resource/resource.h"
 #include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
+namespace metrics
+{
+class Meter;
+}  // namespace metrics
+
 namespace sdk
 {
 namespace metrics
 {
 
 // forward declaration
+class MeterContext;
 class MetricCollector;
 class MetricReader;
 
@@ -40,7 +46,7 @@ class MeterProvider final : public opentelemetry::metrics::MeterProvider
    * Initialize a new meter provider with a specified context
    * @param context The shared meter configuration/pipeline for this provider.
    */
-  explicit MeterProvider(std::shared_ptr<sdk::metrics::MeterContext> context) noexcept;
+  explicit MeterProvider(std::shared_ptr<MeterContext> context) noexcept;
 
   nostd::shared_ptr<opentelemetry::metrics::Meter> GetMeter(
       nostd::string_view name,
@@ -88,7 +94,7 @@ class MeterProvider final : public opentelemetry::metrics::MeterProvider
   ~MeterProvider() override;
 
 private:
-  std::shared_ptr<sdk::metrics::MeterContext> context_;
+  std::shared_ptr<MeterContext> context_;
   std::mutex lock_;
 };
 }  // namespace metrics
diff --git a/sdk/include/opentelemetry/sdk/metrics/metric_reader.h b/sdk/include/opentelemetry/sdk/metrics/metric_reader.h
index 86101e39a0..96b34a4427 100644
--- a/sdk/include/opentelemetry/sdk/metrics/metric_reader.h
+++ b/sdk/include/opentelemetry/sdk/metrics/metric_reader.h
@@ -3,21 +3,22 @@
 
 #pragma once
 
+#include <chrono>
+#include <memory>
+
 #include "opentelemetry/common/spin_lock_mutex.h"
-#include "opentelemetry/sdk/common/global_log_handler.h"
+#include "opentelemetry/nostd/function_ref.h"
 #include "opentelemetry/sdk/metrics/data/metric_data.h"
-#include "opentelemetry/sdk/metrics/export/metric_producer.h"
 #include "opentelemetry/sdk/metrics/instruments.h"
 #include "opentelemetry/version.h"
 
-#include <chrono>
-#include <memory>
-
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
 {
 namespace metrics
 {
+class MetricProducer;
+struct ResourceMetrics;
 
 /**
  * MetricReader defines the interface to collect metrics from SDK
diff --git a/sdk/include/opentelemetry/sdk/metrics/observer_result.h b/sdk/include/opentelemetry/sdk/metrics/observer_result.h
index 4b6a55e3bc..38c5843633 100644
--- a/sdk/include/opentelemetry/sdk/metrics/observer_result.h
+++ b/sdk/include/opentelemetry/sdk/metrics/observer_result.h
@@ -3,12 +3,13 @@
 
 #pragma once
 
+#include <unordered_map>
+
 #include "opentelemetry/common/key_value_iterable.h"
 #include "opentelemetry/metrics/observer_result.h"
 #include "opentelemetry/sdk/metrics/state/attributes_hashmap.h"
 #include "opentelemetry/sdk/metrics/view/attributes_processor.h"
-
-#include <map>
+#include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
diff --git a/sdk/include/opentelemetry/sdk/metrics/push_metric_exporter.h b/sdk/include/opentelemetry/sdk/metrics/push_metric_exporter.h
index 58e2c68c62..409a826ca9 100644
--- a/sdk/include/opentelemetry/sdk/metrics/push_metric_exporter.h
+++ b/sdk/include/opentelemetry/sdk/metrics/push_metric_exporter.h
@@ -3,21 +3,20 @@
 
 #pragma once
 
-#include "opentelemetry/nostd/span.h"
+#include <chrono>
+
 #include "opentelemetry/sdk/common/exporter_utils.h"
-#include "opentelemetry/sdk/metrics/export/metric_producer.h"
+#include "opentelemetry/sdk/metrics/instruments.h"
 #include "opentelemetry/version.h"
 
-#include <chrono>
-#include <memory>
-
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
 {
 namespace metrics
 {
-
 class MetricData;
+struct ResourceMetrics;
+
 /**
  * PushMetricExporter defines the interface to be used by metrics libraries to
  *  push metrics data to the OpenTelemetry exporters.
diff --git a/sdk/include/opentelemetry/sdk/metrics/state/async_metric_storage.h b/sdk/include/opentelemetry/sdk/metrics/state/async_metric_storage.h
index aad00bb5cf..aada06142a 100644
--- a/sdk/include/opentelemetry/sdk/metrics/state/async_metric_storage.h
+++ b/sdk/include/opentelemetry/sdk/metrics/state/async_metric_storage.h
@@ -3,6 +3,10 @@
 
 #pragma once
 
+#include <memory>
+#include <mutex>
+#include <unordered_map>
+
 #include "opentelemetry/nostd/shared_ptr.h"
 #include "opentelemetry/sdk/common/attributemap_hash.h"
 #include "opentelemetry/sdk/metrics/aggregation/default_aggregation.h"
@@ -14,8 +18,6 @@
 #include "opentelemetry/sdk/metrics/state/temporal_metric_storage.h"
 #include "opentelemetry/sdk/metrics/view/attributes_processor.h"
 
-#include <memory>
-
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
 {
diff --git a/sdk/include/opentelemetry/sdk/metrics/state/metric_collector.h b/sdk/include/opentelemetry/sdk/metrics/state/metric_collector.h
index 95cd8a7d10..e94c005ecc 100644
--- a/sdk/include/opentelemetry/sdk/metrics/state/metric_collector.h
+++ b/sdk/include/opentelemetry/sdk/metrics/state/metric_collector.h
@@ -3,8 +3,12 @@
 
 #pragma once
 
-#include "opentelemetry/sdk/metrics/data/metric_data.h"
+#include <chrono>
+#include <memory>
+
 #include "opentelemetry/sdk/metrics/export/metric_producer.h"
+#include "opentelemetry/sdk/metrics/instruments.h"
+#include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
diff --git a/sdk/include/opentelemetry/sdk/metrics/state/metric_storage.h b/sdk/include/opentelemetry/sdk/metrics/state/metric_storage.h
index 0f8f4ddba7..277b45fbb6 100644
--- a/sdk/include/opentelemetry/sdk/metrics/state/metric_storage.h
+++ b/sdk/include/opentelemetry/sdk/metrics/state/metric_storage.h
@@ -3,14 +3,28 @@
 
 #pragma once
 
-#include "opentelemetry/common/key_value_iterable_view.h"
+#include <memory>
+#include <unordered_map>
+
 #include "opentelemetry/common/timestamp.h"
-#include "opentelemetry/context/context.h"
+#include "opentelemetry/nostd/function_ref.h"
+#include "opentelemetry/nostd/span.h"
 #include "opentelemetry/sdk/metrics/data/metric_data.h"
 #include "opentelemetry/sdk/metrics/instruments.h"
 #include "opentelemetry/sdk/metrics/state/attributes_hashmap.h"
+#include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
+namespace common
+{
+class KeyValueIterable;
+}  // namespace common
+
+namespace context
+{
+class Context;
+}  // namespace context
+
 namespace sdk
 {
 namespace metrics
diff --git a/sdk/include/opentelemetry/sdk/metrics/state/multi_metric_storage.h b/sdk/include/opentelemetry/sdk/metrics/state/multi_metric_storage.h
index 421c12b34c..6202b0c7fb 100644
--- a/sdk/include/opentelemetry/sdk/metrics/state/multi_metric_storage.h
+++ b/sdk/include/opentelemetry/sdk/metrics/state/multi_metric_storage.h
@@ -3,13 +3,26 @@
 
 #pragma once
 
-#include "opentelemetry/common/key_value_iterable_view.h"
+#include <memory>
+#include <unordered_map>
+#include <vector>
+
+#include "opentelemetry/common/timestamp.h"
 #include "opentelemetry/sdk/metrics/instruments.h"
 #include "opentelemetry/sdk/metrics/state/metric_storage.h"
-
-#include <memory>
+#include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
+namespace common
+{
+class KeyValueIterable;
+}  // namespace common
+
+namespace context
+{
+class Context;
+}  // namespace context
+
 namespace sdk
 {
 namespace metrics
diff --git a/sdk/include/opentelemetry/sdk/metrics/state/observable_registry.h b/sdk/include/opentelemetry/sdk/metrics/state/observable_registry.h
index 09c439afa4..5eb5b6d6ff 100644
--- a/sdk/include/opentelemetry/sdk/metrics/state/observable_registry.h
+++ b/sdk/include/opentelemetry/sdk/metrics/state/observable_registry.h
@@ -3,13 +3,14 @@
 
 #pragma once
 
-#include "opentelemetry/common/timestamp.h"
-#include "opentelemetry/metrics/async_instruments.h"
-
 #include <memory>
 #include <mutex>
 #include <vector>
 
+#include "opentelemetry/common/timestamp.h"
+#include "opentelemetry/metrics/async_instruments.h"
+#include "opentelemetry/version.h"
+
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
 {
diff --git a/sdk/include/opentelemetry/sdk/metrics/state/sync_metric_storage.h b/sdk/include/opentelemetry/sdk/metrics/state/sync_metric_storage.h
index b8146872e3..37b0e06707 100644
--- a/sdk/include/opentelemetry/sdk/metrics/state/sync_metric_storage.h
+++ b/sdk/include/opentelemetry/sdk/metrics/state/sync_metric_storage.h
@@ -3,8 +3,18 @@
 
 #pragma once
 
+#include <functional>
+#include <list>
+#include <memory>
+#include <mutex>
+#include <unordered_map>
 #include <utility>
-#include "opentelemetry/common/key_value_iterable_view.h"
+
+#include "opentelemetry/common/spin_lock_mutex.h"
+#include "opentelemetry/nostd/function_ref.h"
+#include "opentelemetry/nostd/shared_ptr.h"
+#include "opentelemetry/nostd/span.h"
+#include "opentelemetry/nostd/string_view.h"
 #include "opentelemetry/sdk/common/attributemap_hash.h"
 #include "opentelemetry/sdk/metrics/aggregation/default_aggregation.h"
 #include "opentelemetry/sdk/metrics/exemplar/reservoir.h"
@@ -14,9 +24,7 @@
 
 #include "opentelemetry/sdk/metrics/state/temporal_metric_storage.h"
 #include "opentelemetry/sdk/metrics/view/attributes_processor.h"
-
-#include <list>
-#include <memory>
+#include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
diff --git a/sdk/include/opentelemetry/sdk/metrics/state/temporal_metric_storage.h b/sdk/include/opentelemetry/sdk/metrics/state/temporal_metric_storage.h
index 4ddc593149..0a08e7d100 100644
--- a/sdk/include/opentelemetry/sdk/metrics/state/temporal_metric_storage.h
+++ b/sdk/include/opentelemetry/sdk/metrics/state/temporal_metric_storage.h
@@ -3,19 +3,26 @@
 
 #pragma once
 
-#include "opentelemetry/nostd/shared_ptr.h"
-#include "opentelemetry/sdk/metrics/aggregation/default_aggregation.h"
-#include "opentelemetry/sdk/metrics/state/attributes_hashmap.h"
-#include "opentelemetry/sdk/metrics/state/metric_collector.h"
-
 #include <list>
 #include <memory>
+#include <unordered_map>
+
+#include "opentelemetry/common/spin_lock_mutex.h"
+#include "opentelemetry/common/timestamp.h"
+#include "opentelemetry/nostd/function_ref.h"
+#include "opentelemetry/nostd/span.h"
+#include "opentelemetry/sdk/metrics/instruments.h"
+#include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
 {
 namespace metrics
 {
+class AggregationConfig;
+class AttributesHashMap;
+class CollectorHandle;
+class MetricData;
 
 struct LastReportedMetrics
 {
diff --git a/sdk/include/opentelemetry/sdk/metrics/sync_instruments.h b/sdk/include/opentelemetry/sdk/metrics/sync_instruments.h
index 803191170c..825547a846 100644
--- a/sdk/include/opentelemetry/sdk/metrics/sync_instruments.h
+++ b/sdk/include/opentelemetry/sdk/metrics/sync_instruments.h
@@ -3,14 +3,13 @@
 
 #pragma once
 
-#include "opentelemetry/common/key_value_iterable.h"
+#include <memory>
+
 #include "opentelemetry/metrics/sync_instruments.h"
-#include "opentelemetry/nostd/string_view.h"
 #include "opentelemetry/sdk/metrics/instruments.h"
 #include "opentelemetry/sdk/metrics/state/metric_storage.h"
 #include "opentelemetry/sdk_config.h"
-
-#include "opentelemetry/sdk/instrumentationscope/instrumentation_scope.h"
+#include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
diff --git a/sdk/include/opentelemetry/sdk/metrics/view/attributes_processor.h b/sdk/include/opentelemetry/sdk/metrics/view/attributes_processor.h
index c3328bfa1e..91e4b268cf 100644
--- a/sdk/include/opentelemetry/sdk/metrics/view/attributes_processor.h
+++ b/sdk/include/opentelemetry/sdk/metrics/view/attributes_processor.h
@@ -3,7 +3,14 @@
 
 #pragma once
 
+#include <string>
+#include <unordered_map>
+
+#include "opentelemetry/common/key_value_iterable.h"
+#include "opentelemetry/nostd/string_view.h"
 #include "opentelemetry/sdk/common/attribute_utils.h"
+#include "opentelemetry/sdk/metrics/instruments.h"
+#include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
diff --git a/sdk/include/opentelemetry/sdk/metrics/view/instrument_selector.h b/sdk/include/opentelemetry/sdk/metrics/view/instrument_selector.h
index a8cf38b49f..2055ed96fa 100644
--- a/sdk/include/opentelemetry/sdk/metrics/view/instrument_selector.h
+++ b/sdk/include/opentelemetry/sdk/metrics/view/instrument_selector.h
@@ -3,9 +3,13 @@
 
 #pragma once
 
+#include <memory>
+
 #include "opentelemetry/nostd/string_view.h"
 #include "opentelemetry/sdk/metrics/instruments.h"
 #include "opentelemetry/sdk/metrics/view/predicate_factory.h"
+#include "opentelemetry/version.h"
+
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
 {
diff --git a/sdk/include/opentelemetry/sdk/metrics/view/meter_selector.h b/sdk/include/opentelemetry/sdk/metrics/view/meter_selector.h
index de61d21412..16d777b71f 100644
--- a/sdk/include/opentelemetry/sdk/metrics/view/meter_selector.h
+++ b/sdk/include/opentelemetry/sdk/metrics/view/meter_selector.h
@@ -3,8 +3,11 @@
 
 #pragma once
 
+#include <memory>
+
 #include "opentelemetry/nostd/string_view.h"
 #include "opentelemetry/sdk/metrics/view/predicate_factory.h"
+#include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
diff --git a/sdk/include/opentelemetry/sdk/metrics/view/predicate_factory.h b/sdk/include/opentelemetry/sdk/metrics/view/predicate_factory.h
index 7df3955873..ba2303ff92 100644
--- a/sdk/include/opentelemetry/sdk/metrics/view/predicate_factory.h
+++ b/sdk/include/opentelemetry/sdk/metrics/view/predicate_factory.h
@@ -3,8 +3,11 @@
 
 #pragma once
 
+#include <memory>
+
 #include "opentelemetry/nostd/string_view.h"
 #include "opentelemetry/sdk/metrics/view/predicate.h"
+#include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
diff --git a/sdk/include/opentelemetry/sdk/metrics/view/view.h b/sdk/include/opentelemetry/sdk/metrics/view/view.h
index 678c53f6c6..2d3edcee0e 100644
--- a/sdk/include/opentelemetry/sdk/metrics/view/view.h
+++ b/sdk/include/opentelemetry/sdk/metrics/view/view.h
@@ -3,12 +3,13 @@
 
 #pragma once
 
-#include "opentelemetry/nostd/shared_ptr.h"
-#include "opentelemetry/nostd/string_view.h"
+#include <memory>
+#include <string>
+
 #include "opentelemetry/sdk/metrics/aggregation/aggregation_config.h"
-#include "opentelemetry/sdk/metrics/aggregation/default_aggregation.h"
 #include "opentelemetry/sdk/metrics/instruments.h"
 #include "opentelemetry/sdk/metrics/view/attributes_processor.h"
+#include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
diff --git a/sdk/include/opentelemetry/sdk/metrics/view/view_registry.h b/sdk/include/opentelemetry/sdk/metrics/view/view_registry.h
index 87773b2091..9f12259665 100644
--- a/sdk/include/opentelemetry/sdk/metrics/view/view_registry.h
+++ b/sdk/include/opentelemetry/sdk/metrics/view/view_registry.h
@@ -3,11 +3,16 @@
 
 #pragma once
 
+#include <memory>
 #include <unordered_map>
+#include <vector>
+
+#include "opentelemetry/nostd/function_ref.h"
 #include "opentelemetry/sdk/instrumentationscope/instrumentation_scope.h"
 #include "opentelemetry/sdk/metrics/view/instrument_selector.h"
 #include "opentelemetry/sdk/metrics/view/meter_selector.h"
 #include "opentelemetry/sdk/metrics/view/view.h"
+#include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
diff --git a/sdk/include/opentelemetry/sdk/resource/resource.h b/sdk/include/opentelemetry/sdk/resource/resource.h
index 09da0b8c97..d578491d78 100644
--- a/sdk/include/opentelemetry/sdk/resource/resource.h
+++ b/sdk/include/opentelemetry/sdk/resource/resource.h
@@ -3,18 +3,11 @@
 
 #pragma once
 
-#include "opentelemetry/common/attribute_value.h"
-#include "opentelemetry/common/key_value_iterable_view.h"
+#include <string>
 
 #include "opentelemetry/sdk/common/attribute_utils.h"
-#include "opentelemetry/sdk/resource/resource_detector.h"
-#include "opentelemetry/sdk/version/version.h"
 #include "opentelemetry/version.h"
 
-#include <memory>
-#include <sstream>
-#include <unordered_map>
-
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
 {
diff --git a/sdk/include/opentelemetry/sdk/resource/resource_detector.h b/sdk/include/opentelemetry/sdk/resource/resource_detector.h
index 6447a2660d..dcbd874847 100644
--- a/sdk/include/opentelemetry/sdk/resource/resource_detector.h
+++ b/sdk/include/opentelemetry/sdk/resource/resource_detector.h
@@ -3,7 +3,7 @@
 
 #pragma once
 
-#include "opentelemetry/nostd/unique_ptr.h"
+#include "opentelemetry/sdk/resource/resource.h"
 #include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
@@ -12,8 +12,6 @@ namespace sdk
 namespace resource
 {
 
-class Resource;
-
 /**
  * Interface for a Resource Detector
  */
diff --git a/sdk/include/opentelemetry/sdk/trace/batch_span_processor.h b/sdk/include/opentelemetry/sdk/trace/batch_span_processor.h
index 60e93d8a9f..34d499a2ef 100644
--- a/sdk/include/opentelemetry/sdk/trace/batch_span_processor.h
+++ b/sdk/include/opentelemetry/sdk/trace/batch_span_processor.h
@@ -3,21 +3,23 @@
 
 #pragma once
 
-#include "opentelemetry/sdk/common/circular_buffer.h"
-#include "opentelemetry/sdk/trace/batch_span_processor_options.h"
-#include "opentelemetry/sdk/trace/exporter.h"
-#include "opentelemetry/sdk/trace/processor.h"
-
 #include <atomic>
 #include <condition_variable>
+#include <memory>
+#include <mutex>
 #include <thread>
 
+#include "opentelemetry/sdk/common/circular_buffer.h"
+#include "opentelemetry/sdk/trace/processor.h"
+#include "opentelemetry/version.h"
+
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
 {
-
 namespace trace
 {
+class SpanExporter;
+struct BatchSpanProcessorOptions;
 
 /**
  * This is an implementation of the SpanProcessor which creates batches of finished spans and passes
diff --git a/sdk/include/opentelemetry/sdk/trace/batch_span_processor_factory.h b/sdk/include/opentelemetry/sdk/trace/batch_span_processor_factory.h
index 6e66d2d2b9..4f645b2633 100644
--- a/sdk/include/opentelemetry/sdk/trace/batch_span_processor_factory.h
+++ b/sdk/include/opentelemetry/sdk/trace/batch_span_processor_factory.h
@@ -5,16 +5,16 @@
 
 #include <memory>
 
-#include "opentelemetry/sdk/trace/batch_span_processor_options.h"
-#include "opentelemetry/sdk/trace/exporter.h"
-#include "opentelemetry/sdk/trace/processor.h"
-#include "opentelemetry/sdk/version/version.h"
+#include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
 {
 namespace trace
 {
+class SpanExporter;
+class SpanProcessor;
+struct BatchSpanProcessorOptions;
 
 /**
  * Factory class for BatchSpanProcessor.
diff --git a/sdk/include/opentelemetry/sdk/trace/batch_span_processor_options.h b/sdk/include/opentelemetry/sdk/trace/batch_span_processor_options.h
index 053126c065..ac1052383b 100644
--- a/sdk/include/opentelemetry/sdk/trace/batch_span_processor_options.h
+++ b/sdk/include/opentelemetry/sdk/trace/batch_span_processor_options.h
@@ -3,10 +3,10 @@
 
 #pragma once
 
-#include "opentelemetry/sdk/version/version.h"
-
 #include <chrono>
 
+#include "opentelemetry/version.h"
+
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
 {
diff --git a/sdk/include/opentelemetry/sdk/trace/exporter.h b/sdk/include/opentelemetry/sdk/trace/exporter.h
index ffacca2b35..f9ed068b64 100644
--- a/sdk/include/opentelemetry/sdk/trace/exporter.h
+++ b/sdk/include/opentelemetry/sdk/trace/exporter.h
@@ -3,16 +3,20 @@
 
 #pragma once
 
+#include <chrono>
 #include <memory>
+
 #include "opentelemetry/nostd/span.h"
 #include "opentelemetry/sdk/common/exporter_utils.h"
-#include "opentelemetry/sdk/trace/recordable.h"
+#include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
 {
 namespace trace
 {
+class Recordable;
+
 /**
  * SpanExporter defines the interface that protocol-specific span exporters must
  * implement.
@@ -40,8 +44,7 @@ class OPENTELEMETRY_EXPORT SpanExporter
    * @param spans a span of unique pointers to span recordables
    */
   virtual sdk::common::ExportResult Export(
-      const nostd::span<std::unique_ptr<opentelemetry::sdk::trace::Recordable>>
-          &spans) noexcept = 0;
+      const nostd::span<std::unique_ptr<Recordable>> &spans) noexcept = 0;
 
   /**
    * Export all spans that have been exported.
diff --git a/sdk/include/opentelemetry/sdk/trace/id_generator.h b/sdk/include/opentelemetry/sdk/trace/id_generator.h
index 559870d961..bd807ff89a 100644
--- a/sdk/include/opentelemetry/sdk/trace/id_generator.h
+++ b/sdk/include/opentelemetry/sdk/trace/id_generator.h
@@ -2,6 +2,7 @@
 // SPDX-License-Identifier: Apache-2.0
 
 #pragma once
+
 #include "opentelemetry/trace/span_id.h"
 #include "opentelemetry/trace/trace_id.h"
 #include "opentelemetry/version.h"
diff --git a/sdk/include/opentelemetry/sdk/trace/multi_recordable.h b/sdk/include/opentelemetry/sdk/trace/multi_recordable.h
index 6abd39f90b..8519591286 100644
--- a/sdk/include/opentelemetry/sdk/trace/multi_recordable.h
+++ b/sdk/include/opentelemetry/sdk/trace/multi_recordable.h
@@ -3,13 +3,13 @@
 
 #pragma once
 
+#include <map>
+
 #include "opentelemetry/common/timestamp.h"
 #include "opentelemetry/sdk/trace/processor.h"
 #include "opentelemetry/sdk/trace/recordable.h"
 #include "opentelemetry/version.h"
 
-#include <map>
-
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
 {
diff --git a/sdk/include/opentelemetry/sdk/trace/multi_span_processor.h b/sdk/include/opentelemetry/sdk/trace/multi_span_processor.h
index e3b4a2031e..094c5b3e24 100644
--- a/sdk/include/opentelemetry/sdk/trace/multi_span_processor.h
+++ b/sdk/include/opentelemetry/sdk/trace/multi_span_processor.h
@@ -3,13 +3,14 @@
 
 #pragma once
 
+#include <chrono>
+#include <memory>
 #include <mutex>
 #include <vector>
 
 #include "opentelemetry/sdk/trace/multi_recordable.h"
 #include "opentelemetry/sdk/trace/processor.h"
-
-#include <iostream>
+#include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
diff --git a/sdk/include/opentelemetry/sdk/trace/processor.h b/sdk/include/opentelemetry/sdk/trace/processor.h
index f87b893837..3701422eb5 100644
--- a/sdk/include/opentelemetry/sdk/trace/processor.h
+++ b/sdk/include/opentelemetry/sdk/trace/processor.h
@@ -5,13 +5,21 @@
 
 #include <chrono>
 #include <memory>
-#include "opentelemetry/sdk/trace/recordable.h"
+
+#include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
+namespace trace
+{
+class SpanContext;
+}  // namespace trace
+
 namespace sdk
 {
 namespace trace
 {
+class Recordable;
+
 /**
  * Span processor allow hooks for span start and end method invocations.
  *
diff --git a/sdk/include/opentelemetry/sdk/trace/random_id_generator.h b/sdk/include/opentelemetry/sdk/trace/random_id_generator.h
index 59df91651f..f06f02f5e7 100644
--- a/sdk/include/opentelemetry/sdk/trace/random_id_generator.h
+++ b/sdk/include/opentelemetry/sdk/trace/random_id_generator.h
@@ -2,7 +2,9 @@
 // SPDX-License-Identifier: Apache-2.0
 
 #pragma once
+
 #include "opentelemetry/sdk/trace/id_generator.h"
+#include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
diff --git a/sdk/include/opentelemetry/sdk/trace/random_id_generator_factory.h b/sdk/include/opentelemetry/sdk/trace/random_id_generator_factory.h
index 1b8f7e3c3b..6c94984403 100644
--- a/sdk/include/opentelemetry/sdk/trace/random_id_generator_factory.h
+++ b/sdk/include/opentelemetry/sdk/trace/random_id_generator_factory.h
@@ -5,13 +5,14 @@
 
 #include <memory>
 
-#include "opentelemetry/sdk/trace/id_generator.h"
+#include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
 {
 namespace trace
 {
+class IdGenerator;
 
 /**
  * Factory class for RandomIdGenerator.
diff --git a/sdk/include/opentelemetry/sdk/trace/recordable.h b/sdk/include/opentelemetry/sdk/trace/recordable.h
index 721e33232d..cb73ef5f64 100644
--- a/sdk/include/opentelemetry/sdk/trace/recordable.h
+++ b/sdk/include/opentelemetry/sdk/trace/recordable.h
@@ -3,27 +3,33 @@
 
 #pragma once
 
+#include <chrono>
+
 #include "opentelemetry/common/attribute_value.h"
-#include "opentelemetry/common/key_value_iterable.h"
 #include "opentelemetry/common/timestamp.h"
 #include "opentelemetry/nostd/string_view.h"
 #include "opentelemetry/sdk/common/empty_attributes.h"
 #include "opentelemetry/sdk/instrumentationscope/instrumentation_scope.h"
-#include "opentelemetry/sdk/resource/resource.h"
-#include "opentelemetry/trace/canonical_code.h"
-#include "opentelemetry/trace/span.h"
 #include "opentelemetry/trace/span_context.h"
 #include "opentelemetry/trace/span_id.h"
-#include "opentelemetry/trace/trace_id.h"
+#include "opentelemetry/trace/span_metadata.h"
 #include "opentelemetry/version.h"
 
-#include <map>
-
 // TODO: Create generic short pattern for opentelemetry::common and opentelemetry::trace
 
 OPENTELEMETRY_BEGIN_NAMESPACE
+namespace common
+{
+class KeyValueIterable;
+}  // namespace common
+
 namespace sdk
 {
+namespace resource
+{
+class Resource;
+}  // namespace resource
+
 namespace trace
 {
 
diff --git a/sdk/include/opentelemetry/sdk/trace/sampler.h b/sdk/include/opentelemetry/sdk/trace/sampler.h
index 799d490e8b..b90a2e66b2 100644
--- a/sdk/include/opentelemetry/sdk/trace/sampler.h
+++ b/sdk/include/opentelemetry/sdk/trace/sampler.h
@@ -3,19 +3,30 @@
 
 #pragma once
 
-#include "opentelemetry/common/attribute_value.h"
-#include "opentelemetry/trace/span.h"
-#include "opentelemetry/trace/span_context.h"
-#include "opentelemetry/trace/span_context_kv_iterable.h"
-#include "opentelemetry/trace/trace_id.h"
-#include "opentelemetry/trace/trace_state.h"
-#include "opentelemetry/version.h"
-
 #include <map>
 #include <memory>
 #include <string>
 
+#include "opentelemetry/common/attribute_value.h"
+#include "opentelemetry/nostd/shared_ptr.h"
+#include "opentelemetry/nostd/string_view.h"
+#include "opentelemetry/trace/span_metadata.h"
+#include "opentelemetry/trace/trace_id.h"
+#include "opentelemetry/version.h"
+
 OPENTELEMETRY_BEGIN_NAMESPACE
+namespace common
+{
+class KeyValueIterable;
+}  // namespace common
+
+namespace trace
+{
+class SpanContext;
+class SpanContextKeyValueIterable;
+class TraceState;
+}  // namespace trace
+
 namespace sdk
 {
 namespace trace
diff --git a/sdk/include/opentelemetry/sdk/trace/samplers/always_off.h b/sdk/include/opentelemetry/sdk/trace/samplers/always_off.h
index 2392b9b2fb..a857086d23 100644
--- a/sdk/include/opentelemetry/sdk/trace/samplers/always_off.h
+++ b/sdk/include/opentelemetry/sdk/trace/samplers/always_off.h
@@ -3,7 +3,12 @@
 
 #pragma once
 
+#include "opentelemetry/nostd/string_view.h"
 #include "opentelemetry/sdk/trace/sampler.h"
+#include "opentelemetry/trace/span_context.h"
+#include "opentelemetry/trace/span_metadata.h"
+#include "opentelemetry/trace/trace_id.h"
+#include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
diff --git a/sdk/include/opentelemetry/sdk/trace/samplers/always_off_factory.h b/sdk/include/opentelemetry/sdk/trace/samplers/always_off_factory.h
index 2ae09b229c..19f76c715f 100644
--- a/sdk/include/opentelemetry/sdk/trace/samplers/always_off_factory.h
+++ b/sdk/include/opentelemetry/sdk/trace/samplers/always_off_factory.h
@@ -5,13 +5,14 @@
 
 #include <memory>
 
-#include "opentelemetry/sdk/trace/sampler.h"
+#include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
 {
 namespace trace
 {
+class Sampler;
 
 /**
  * Factory class for AlwaysOffSampler.
diff --git a/sdk/include/opentelemetry/sdk/trace/samplers/always_on.h b/sdk/include/opentelemetry/sdk/trace/samplers/always_on.h
index 6c8583599d..6b983008c7 100644
--- a/sdk/include/opentelemetry/sdk/trace/samplers/always_on.h
+++ b/sdk/include/opentelemetry/sdk/trace/samplers/always_on.h
@@ -3,9 +3,24 @@
 
 #pragma once
 
+#include "opentelemetry/nostd/string_view.h"
 #include "opentelemetry/sdk/trace/sampler.h"
+#include "opentelemetry/trace/span_context.h"
+#include "opentelemetry/trace/span_metadata.h"
+#include "opentelemetry/trace/trace_id.h"
+#include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
+namespace common
+{
+class KeyValueIterable;
+}  // namespace common
+
+namespace trace
+{
+class SpanContextKeyValueIterable;
+}  // namespace trace
+
 namespace sdk
 {
 namespace trace
diff --git a/sdk/include/opentelemetry/sdk/trace/samplers/always_on_factory.h b/sdk/include/opentelemetry/sdk/trace/samplers/always_on_factory.h
index 3484f0d4fa..c72d97fdec 100644
--- a/sdk/include/opentelemetry/sdk/trace/samplers/always_on_factory.h
+++ b/sdk/include/opentelemetry/sdk/trace/samplers/always_on_factory.h
@@ -5,13 +5,14 @@
 
 #include <memory>
 
-#include "opentelemetry/sdk/trace/sampler.h"
+#include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
 {
 namespace trace
 {
+class Sampler;
 
 /**
  * Factory class for AlwaysOnSampler.
diff --git a/sdk/include/opentelemetry/sdk/trace/samplers/parent.h b/sdk/include/opentelemetry/sdk/trace/samplers/parent.h
index c76a6c2a58..59dd314589 100644
--- a/sdk/include/opentelemetry/sdk/trace/samplers/parent.h
+++ b/sdk/include/opentelemetry/sdk/trace/samplers/parent.h
@@ -3,10 +3,25 @@
 
 #pragma once
 
-#include "opentelemetry/sdk/common/atomic_shared_ptr.h"
+#include <memory>
+
+#include "opentelemetry/nostd/string_view.h"
 #include "opentelemetry/sdk/trace/sampler.h"
+#include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
+namespace common
+{
+class KeyValueIterable;
+}  // namespace common
+
+namespace trace
+{
+class SpanContext;
+class SpanContextKeyValueIterable;
+class TraceState;
+}  // namespace trace
+
 namespace sdk
 {
 namespace trace
diff --git a/sdk/include/opentelemetry/sdk/trace/samplers/parent_factory.h b/sdk/include/opentelemetry/sdk/trace/samplers/parent_factory.h
index 006bdab1da..2fdf87819d 100644
--- a/sdk/include/opentelemetry/sdk/trace/samplers/parent_factory.h
+++ b/sdk/include/opentelemetry/sdk/trace/samplers/parent_factory.h
@@ -5,13 +5,14 @@
 
 #include <memory>
 
-#include "opentelemetry/sdk/trace/sampler.h"
+#include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
 {
 namespace trace
 {
+class Sampler;
 
 /**
  * Factory class for ParentBasedSampler.
diff --git a/sdk/include/opentelemetry/sdk/trace/samplers/trace_id_ratio.h b/sdk/include/opentelemetry/sdk/trace/samplers/trace_id_ratio.h
index 407b480d62..b5df576091 100644
--- a/sdk/include/opentelemetry/sdk/trace/samplers/trace_id_ratio.h
+++ b/sdk/include/opentelemetry/sdk/trace/samplers/trace_id_ratio.h
@@ -3,9 +3,27 @@
 
 #pragma once
 
+#include <string>
+
+#include "opentelemetry/nostd/string_view.h"
 #include "opentelemetry/sdk/trace/sampler.h"
+#include "opentelemetry/trace/span_metadata.h"
+#include "opentelemetry/trace/trace_id.h"
+#include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
+namespace common
+{
+class KeyValueIterable;
+}  // namespace common
+
+namespace trace
+{
+class SpanContext;
+class SpanContextKeyValueIterable;
+class TraceState;
+}  // namespace trace
+
 namespace sdk
 {
 namespace trace
diff --git a/sdk/include/opentelemetry/sdk/trace/samplers/trace_id_ratio_factory.h b/sdk/include/opentelemetry/sdk/trace/samplers/trace_id_ratio_factory.h
index 79728ba200..eb434fc6fe 100644
--- a/sdk/include/opentelemetry/sdk/trace/samplers/trace_id_ratio_factory.h
+++ b/sdk/include/opentelemetry/sdk/trace/samplers/trace_id_ratio_factory.h
@@ -5,13 +5,14 @@
 
 #include <memory>
 
-#include "opentelemetry/sdk/trace/sampler.h"
+#include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
 {
 namespace trace
 {
+class Sampler;
 
 /**
  * Factory class for TraceIdRatioBasedSampler.
diff --git a/sdk/include/opentelemetry/sdk/trace/simple_processor.h b/sdk/include/opentelemetry/sdk/trace/simple_processor.h
index 671218d0cf..dee8e80bb8 100644
--- a/sdk/include/opentelemetry/sdk/trace/simple_processor.h
+++ b/sdk/include/opentelemetry/sdk/trace/simple_processor.h
@@ -4,11 +4,16 @@
 #pragma once
 
 #include <atomic>
+#include <chrono>
+#include <memory>
 #include <mutex>
 
 #include "opentelemetry/common/spin_lock_mutex.h"
+#include "opentelemetry/nostd/span.h"
 #include "opentelemetry/sdk/trace/exporter.h"
 #include "opentelemetry/sdk/trace/processor.h"
+#include "opentelemetry/sdk/trace/recordable.h"
+#include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
diff --git a/sdk/include/opentelemetry/sdk/trace/simple_processor_factory.h b/sdk/include/opentelemetry/sdk/trace/simple_processor_factory.h
index efa3078a38..6a106e7f21 100644
--- a/sdk/include/opentelemetry/sdk/trace/simple_processor_factory.h
+++ b/sdk/include/opentelemetry/sdk/trace/simple_processor_factory.h
@@ -5,14 +5,15 @@
 
 #include <memory>
 
-#include "opentelemetry/sdk/trace/exporter.h"
-#include "opentelemetry/sdk/trace/processor.h"
+#include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
 {
 namespace trace
 {
+class SpanExporter;
+class SpanProcessor;
 
 /**
  * Factory class for SimpleSpanProcessor.
diff --git a/sdk/include/opentelemetry/sdk/trace/span_data.h b/sdk/include/opentelemetry/sdk/trace/span_data.h
index 61a7ced6fe..4e1a52ce5d 100644
--- a/sdk/include/opentelemetry/sdk/trace/span_data.h
+++ b/sdk/include/opentelemetry/sdk/trace/span_data.h
@@ -4,20 +4,23 @@
 #pragma once
 
 #include <chrono>
+#include <map>
+#include <memory>
+#include <string>
 #include <unordered_map>
 #include <vector>
+
 #include "opentelemetry/common/attribute_value.h"
 #include "opentelemetry/common/macros.h"
 #include "opentelemetry/common/timestamp.h"
 #include "opentelemetry/nostd/string_view.h"
 #include "opentelemetry/sdk/common/attribute_utils.h"
+#include "opentelemetry/sdk/resource/resource.h"
 #include "opentelemetry/sdk/trace/recordable.h"
-#include "opentelemetry/trace/canonical_code.h"
 #include "opentelemetry/trace/span.h"
 #include "opentelemetry/trace/span_id.h"
 #include "opentelemetry/trace/trace_id.h"
-
-#include <string>
+#include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
diff --git a/sdk/include/opentelemetry/sdk/trace/tracer.h b/sdk/include/opentelemetry/sdk/trace/tracer.h
index 3ac17aad66..67e606ba97 100644
--- a/sdk/include/opentelemetry/sdk/trace/tracer.h
+++ b/sdk/include/opentelemetry/sdk/trace/tracer.h
@@ -3,40 +3,46 @@
 
 #pragma once
 
+#include <memory>
+
 #include "opentelemetry/common/macros.h"
-#include "opentelemetry/sdk/common/atomic_shared_ptr.h"
+#include "opentelemetry/nostd/shared_ptr.h"
+#include "opentelemetry/nostd/string_view.h"
 #include "opentelemetry/sdk/instrumentationscope/instrumentation_scope.h"
-#include "opentelemetry/sdk/resource/resource.h"
-#include "opentelemetry/sdk/trace/processor.h"
 #include "opentelemetry/sdk/trace/samplers/always_on.h"
 #include "opentelemetry/sdk/trace/tracer_context.h"
-#include "opentelemetry/trace/noop.h"
 #include "opentelemetry/trace/tracer.h"
 #include "opentelemetry/version.h"
 
-#include <memory>
-
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
 {
+namespace resource
+{
+class Resource;
+}  // namespace resource
+
 namespace trace
 {
+class IdGenerator;
+class SpanProcessor;
 
 using namespace opentelemetry::sdk::instrumentationscope;
 
-class Tracer final : public trace_api::Tracer, public std::enable_shared_from_this<Tracer>
+class Tracer final : public opentelemetry::trace::Tracer,
+                     public std::enable_shared_from_this<Tracer>
 {
 public:
   /** Construct a new Tracer with the given context pipeline. */
-  explicit Tracer(std::shared_ptr<sdk::trace::TracerContext> context,
+  explicit Tracer(std::shared_ptr<TracerContext> context,
                   std::unique_ptr<InstrumentationScope> instrumentation_scope =
                       InstrumentationScope::Create("")) noexcept;
 
-  nostd::shared_ptr<trace_api::Span> StartSpan(
+  nostd::shared_ptr<opentelemetry::trace::Span> StartSpan(
       nostd::string_view name,
       const opentelemetry::common::KeyValueIterable &attributes,
-      const trace_api::SpanContextKeyValueIterable &links,
-      const trace_api::StartSpanOptions &options = {}) noexcept override;
+      const opentelemetry::trace::SpanContextKeyValueIterable &links,
+      const opentelemetry::trace::StartSpanOptions &options = {}) noexcept override;
 
   void ForceFlushWithMicroseconds(uint64_t timeout) noexcept override;
 
@@ -70,7 +76,7 @@ class Tracer final : public trace_api::Tracer, public std::enable_shared_from_th
   // order of declaration is important here - instrumentation scope should destroy after
   // tracer-context.
   std::shared_ptr<InstrumentationScope> instrumentation_scope_;
-  std::shared_ptr<sdk::trace::TracerContext> context_;
+  std::shared_ptr<TracerContext> context_;
 };
 }  // namespace trace
 }  // namespace sdk
diff --git a/sdk/include/opentelemetry/sdk/trace/tracer_context.h b/sdk/include/opentelemetry/sdk/trace/tracer_context.h
index 6dcdda8e01..9475c8c0b9 100644
--- a/sdk/include/opentelemetry/sdk/trace/tracer_context.h
+++ b/sdk/include/opentelemetry/sdk/trace/tracer_context.h
@@ -3,7 +3,10 @@
 
 #pragma once
 
-#include "opentelemetry/sdk/common/atomic_unique_ptr.h"
+#include <chrono>
+#include <memory>
+#include <vector>
+
 #include "opentelemetry/sdk/resource/resource.h"
 #include "opentelemetry/sdk/trace/processor.h"
 #include "opentelemetry/sdk/trace/random_id_generator.h"
diff --git a/sdk/include/opentelemetry/sdk/trace/tracer_context_factory.h b/sdk/include/opentelemetry/sdk/trace/tracer_context_factory.h
index b03ae297fc..1911db8f93 100644
--- a/sdk/include/opentelemetry/sdk/trace/tracer_context_factory.h
+++ b/sdk/include/opentelemetry/sdk/trace/tracer_context_factory.h
@@ -3,16 +3,25 @@
 
 #pragma once
 
-#include "opentelemetry/sdk/resource/resource.h"
-#include "opentelemetry/sdk/trace/processor.h"
-#include "opentelemetry/sdk/trace/tracer_context.h"
+#include <memory>
+#include <vector>
+
 #include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
 {
+namespace resource
+{
+class Resource;
+}  // namespace resource
+
 namespace trace
 {
+class IdGenerator;
+class Sampler;
+class SpanProcessor;
+class TracerContext;
 
 /**
  * Factory class for TracerContext.
diff --git a/sdk/include/opentelemetry/sdk/trace/tracer_provider.h b/sdk/include/opentelemetry/sdk/trace/tracer_provider.h
index 06088738c2..e15f686898 100644
--- a/sdk/include/opentelemetry/sdk/trace/tracer_provider.h
+++ b/sdk/include/opentelemetry/sdk/trace/tracer_provider.h
@@ -10,18 +10,22 @@
 #include <vector>
 
 #include "opentelemetry/nostd/shared_ptr.h"
+#include "opentelemetry/nostd/string_view.h"
 #include "opentelemetry/sdk/resource/resource.h"
-#include "opentelemetry/sdk/trace/processor.h"
+#include "opentelemetry/sdk/trace/random_id_generator.h"
 #include "opentelemetry/sdk/trace/samplers/always_on.h"
-#include "opentelemetry/sdk/trace/tracer.h"
-#include "opentelemetry/sdk/trace/tracer_context.h"
 #include "opentelemetry/trace/tracer_provider.h"
+#include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
 {
 namespace trace
 {
+class SpanProcessor;
+class Tracer;
+class TracerContext;
+
 class TracerProvider final : public opentelemetry::trace::TracerProvider
 {
 public:
@@ -40,24 +44,22 @@ class TracerProvider final : public opentelemetry::trace::TracerProvider
       opentelemetry::sdk::resource::Resource resource =
           opentelemetry::sdk::resource::Resource::Create({}),
       std::unique_ptr<Sampler> sampler = std::unique_ptr<AlwaysOnSampler>(new AlwaysOnSampler),
-      std::unique_ptr<opentelemetry::sdk::trace::IdGenerator> id_generator =
-          std::unique_ptr<opentelemetry::sdk::trace::IdGenerator>(
-              new RandomIdGenerator())) noexcept;
+      std::unique_ptr<IdGenerator> id_generator =
+          std::unique_ptr<IdGenerator>(new RandomIdGenerator())) noexcept;
 
   explicit TracerProvider(
       std::vector<std::unique_ptr<SpanProcessor>> &&processors,
       opentelemetry::sdk::resource::Resource resource =
           opentelemetry::sdk::resource::Resource::Create({}),
       std::unique_ptr<Sampler> sampler = std::unique_ptr<AlwaysOnSampler>(new AlwaysOnSampler),
-      std::unique_ptr<opentelemetry::sdk::trace::IdGenerator> id_generator =
-          std::unique_ptr<opentelemetry::sdk::trace::IdGenerator>(
-              new RandomIdGenerator())) noexcept;
+      std::unique_ptr<IdGenerator> id_generator =
+          std::unique_ptr<IdGenerator>(new RandomIdGenerator())) noexcept;
 
   /**
    * Initialize a new tracer provider with a specified context
    * @param context The shared tracer configuration/pipeline for this provider.
    */
-  explicit TracerProvider(std::shared_ptr<sdk::trace::TracerContext> context) noexcept;
+  explicit TracerProvider(std::shared_ptr<TracerContext> context) noexcept;
 
   ~TracerProvider() override;
 
@@ -94,8 +96,8 @@ class TracerProvider final : public opentelemetry::trace::TracerProvider
 
 private:
   // order of declaration is important here - tracers should destroy only after context.
-  std::vector<std::shared_ptr<opentelemetry::sdk::trace::Tracer>> tracers_;
-  std::shared_ptr<sdk::trace::TracerContext> context_;
+  std::vector<std::shared_ptr<Tracer>> tracers_;
+  std::shared_ptr<TracerContext> context_;
   std::mutex lock_;
 };
 }  // namespace trace
diff --git a/sdk/include/opentelemetry/sdk/trace/tracer_provider_factory.h b/sdk/include/opentelemetry/sdk/trace/tracer_provider_factory.h
index 14458b2409..93bd1085ac 100644
--- a/sdk/include/opentelemetry/sdk/trace/tracer_provider_factory.h
+++ b/sdk/include/opentelemetry/sdk/trace/tracer_provider_factory.h
@@ -4,16 +4,29 @@
 #pragma once
 
 #include <memory>
+#include <vector>
 
-#include "opentelemetry/sdk/trace/processor.h"
-#include "opentelemetry/sdk/trace/tracer_context.h"
-#include "opentelemetry/trace/tracer_provider.h"
+#include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
+namespace trace
+{
+class TracerProvider;
+}  // namespace trace
+
 namespace sdk
 {
+namespace resource
+{
+class Resource;
+}  // namespace resource
+
 namespace trace
 {
+class IdGenerator;
+class Sampler;
+class SpanProcessor;
+class TracerContext;
 
 /**
  * Factory class for TracerProvider.
@@ -65,7 +78,7 @@ class OPENTELEMETRY_EXPORT TracerProviderFactory
   /* Create with a tracer context. */
 
   static std::unique_ptr<opentelemetry::trace::TracerProvider> Create(
-      std::shared_ptr<sdk::trace::TracerContext> context);
+      std::shared_ptr<TracerContext> context);
 };
 
 }  // namespace trace
diff --git a/sdk/src/common/global_log_handler.cc b/sdk/src/common/global_log_handler.cc
index 040e3e2154..bd1b56a9cd 100644
--- a/sdk/src/common/global_log_handler.cc
+++ b/sdk/src/common/global_log_handler.cc
@@ -3,8 +3,7 @@
 
 #include "opentelemetry/sdk/common/global_log_handler.h"
 
-#include <cstring>
-#include <random>
+#include <iostream>
 
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
diff --git a/sdk/src/logs/batch_log_record_processor.cc b/sdk/src/logs/batch_log_record_processor.cc
index 6b1db1c666..5487d70e80 100644
--- a/sdk/src/logs/batch_log_record_processor.cc
+++ b/sdk/src/logs/batch_log_record_processor.cc
@@ -2,10 +2,14 @@
 // SPDX-License-Identifier: Apache-2.0
 
 #ifdef ENABLE_LOGS_PREVIEW
+
 #  include "opentelemetry/sdk/logs/batch_log_record_processor.h"
 #  include "opentelemetry/common/spin_lock_mutex.h"
+#  include "opentelemetry/common/timestamp.h"
+#  include "opentelemetry/sdk/logs/recordable.h"
 
 #  include <vector>
+
 using opentelemetry::sdk::common::AtomicUniquePtr;
 using opentelemetry::sdk::common::CircularBufferRange;
 
diff --git a/sdk/src/logs/logger.cc b/sdk/src/logs/logger.cc
index 4c76b198bb..e9ebb8bdc4 100644
--- a/sdk/src/logs/logger.cc
+++ b/sdk/src/logs/logger.cc
@@ -2,8 +2,11 @@
 // SPDX-License-Identifier: Apache-2.0
 
 #ifdef ENABLE_LOGS_PREVIEW
+
 #  include "opentelemetry/sdk/logs/logger.h"
 #  include "opentelemetry/context/runtime_context.h"
+#  include "opentelemetry/sdk/logs/processor.h"
+#  include "opentelemetry/sdk/logs/recordable.h"
 #  include "opentelemetry/sdk_config.h"
 #  include "opentelemetry/trace/provider.h"
 
@@ -47,10 +50,10 @@ nostd::unique_ptr<opentelemetry::logs::LogRecord> Logger::CreateLogRecord() noex
     opentelemetry::context::ContextValue context_value =
         opentelemetry::context::RuntimeContext::GetCurrent().GetValue(
             opentelemetry::trace::kSpanKey);
-    if (nostd::holds_alternative<nostd::shared_ptr<trace::Span>>(context_value))
+    if (nostd::holds_alternative<nostd::shared_ptr<opentelemetry::trace::Span>>(context_value))
     {
-      nostd::shared_ptr<trace::Span> &data =
-          nostd::get<nostd::shared_ptr<trace::Span>>(context_value);
+      nostd::shared_ptr<opentelemetry::trace::Span> &data =
+          nostd::get<nostd::shared_ptr<opentelemetry::trace::Span>>(context_value);
       if (data)
       {
         recordable->SetTraceId(data->GetContext().trace_id());
diff --git a/sdk/src/logs/logger_context_factory.cc b/sdk/src/logs/logger_context_factory.cc
index 985743fd67..1fc07f53e5 100644
--- a/sdk/src/logs/logger_context_factory.cc
+++ b/sdk/src/logs/logger_context_factory.cc
@@ -4,6 +4,9 @@
 #ifdef ENABLE_LOGS_PREVIEW
 
 #  include "opentelemetry/sdk/logs/logger_context_factory.h"
+#  include "opentelemetry/sdk/logs/logger_context.h"
+#  include "opentelemetry/sdk/logs/processor.h"
+#  include "opentelemetry/sdk/resource/resource.h"
 
 #  include <memory>
 #  include <vector>
diff --git a/sdk/src/logs/logger_provider.cc b/sdk/src/logs/logger_provider.cc
index 66948b1744..1e1b83c7de 100644
--- a/sdk/src/logs/logger_provider.cc
+++ b/sdk/src/logs/logger_provider.cc
@@ -5,12 +5,10 @@
 
 #  include "opentelemetry/sdk/logs/logger_provider.h"
 #  include "opentelemetry/sdk/common/global_log_handler.h"
-
-#  include <memory>
-#  include <mutex>
-#  include <string>
-#  include <unordered_map>
-#  include <vector>
+#  include "opentelemetry/sdk/instrumentationscope/instrumentation_scope.h"
+#  include "opentelemetry/sdk/logs/logger.h"
+#  include "opentelemetry/sdk/logs/logger_context.h"
+#  include "opentelemetry/sdk/logs/processor.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
diff --git a/sdk/src/logs/multi_log_record_processor.cc b/sdk/src/logs/multi_log_record_processor.cc
index 2859126f80..f6e6c2e176 100644
--- a/sdk/src/logs/multi_log_record_processor.cc
+++ b/sdk/src/logs/multi_log_record_processor.cc
@@ -4,10 +4,8 @@
 #ifdef ENABLE_LOGS_PREVIEW
 
 #  include "opentelemetry/sdk/logs/multi_log_record_processor.h"
-
-#  include <chrono>
-#  include <memory>
-#  include <vector>
+#  include "opentelemetry/sdk/logs/multi_recordable.h"
+#  include "opentelemetry/sdk/logs/recordable.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
diff --git a/sdk/src/logs/readable_log_record.cc b/sdk/src/logs/readable_log_record.cc
index 9ed5ca7ae7..f02d475d47 100644
--- a/sdk/src/logs/readable_log_record.cc
+++ b/sdk/src/logs/readable_log_record.cc
@@ -3,11 +3,14 @@
 
 #ifdef ENABLE_LOGS_PREVIEW
 
+#  include "opentelemetry/sdk/logs/readable_log_record.h"
+#  include "opentelemetry/sdk/instrumentationscope/instrumentation_scope.h"
+#  include "opentelemetry/sdk/resource/resource.h"
+#  include "opentelemetry/sdk/version/version.h"
+
 #  include <cstddef>
 #  include <type_traits>
 
-#  include "opentelemetry/sdk/logs/readable_log_record.h"
-
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
 {
diff --git a/sdk/src/logs/simple_log_record_processor.cc b/sdk/src/logs/simple_log_record_processor.cc
index 50d4c20fdd..6514c7acff 100644
--- a/sdk/src/logs/simple_log_record_processor.cc
+++ b/sdk/src/logs/simple_log_record_processor.cc
@@ -2,10 +2,13 @@
 // SPDX-License-Identifier: Apache-2.0
 
 #ifdef ENABLE_LOGS_PREVIEW
+
 #  include "opentelemetry/sdk/logs/simple_log_record_processor.h"
+#  include "opentelemetry/nostd/span.h"
+#  include "opentelemetry/sdk/logs/exporter.h"
+#  include "opentelemetry/sdk/logs/recordable.h"
 
-#  include <chrono>
-#  include <vector>
+#  include <mutex>
 
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
diff --git a/sdk/src/metrics/aggregation/histogram_aggregation.cc b/sdk/src/metrics/aggregation/histogram_aggregation.cc
index fe01030f13..3213c27f16 100644
--- a/sdk/src/metrics/aggregation/histogram_aggregation.cc
+++ b/sdk/src/metrics/aggregation/histogram_aggregation.cc
@@ -2,6 +2,7 @@
 // SPDX-License-Identifier: Apache-2.0
 
 #include "opentelemetry/sdk/metrics/aggregation/histogram_aggregation.h"
+#include "opentelemetry/sdk/metrics/aggregation/aggregation_config.h"
 #include "opentelemetry/version.h"
 
 #include <algorithm>
diff --git a/sdk/src/metrics/async_instruments.cc b/sdk/src/metrics/async_instruments.cc
index 1d2b1a9552..082d6713b4 100644
--- a/sdk/src/metrics/async_instruments.cc
+++ b/sdk/src/metrics/async_instruments.cc
@@ -3,10 +3,9 @@
 
 #include "opentelemetry/sdk/metrics/async_instruments.h"
 #include "opentelemetry/sdk/metrics/state/metric_storage.h"
+#include "opentelemetry/sdk/metrics/state/observable_registry.h"
 #include "opentelemetry/sdk_config.h"
 
-#include <cmath>
-
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
 {
diff --git a/sdk/src/metrics/meter_context.cc b/sdk/src/metrics/meter_context.cc
index de25153e1d..eaf82232d6 100644
--- a/sdk/src/metrics/meter_context.cc
+++ b/sdk/src/metrics/meter_context.cc
@@ -4,8 +4,10 @@
 #include "opentelemetry/sdk/metrics/meter_context.h"
 #include "opentelemetry/sdk/common/global_log_handler.h"
 #include "opentelemetry/sdk/metrics/metric_reader.h"
+#include "opentelemetry/sdk/metrics/state/metric_collector.h"
 #include "opentelemetry/sdk_config.h"
-#include "opentelemetry/version.h"
+
+#include <mutex>
 
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
diff --git a/sdk/src/metrics/meter_provider.cc b/sdk/src/metrics/meter_provider.cc
index 051ee7269e..1e9dc5f434 100644
--- a/sdk/src/metrics/meter_provider.cc
+++ b/sdk/src/metrics/meter_provider.cc
@@ -3,6 +3,8 @@
 
 #include "opentelemetry/sdk/metrics/meter_provider.h"
 #include "opentelemetry/metrics/meter.h"
+#include "opentelemetry/sdk/metrics/meter.h"
+#include "opentelemetry/sdk/metrics/meter_context.h"
 #include "opentelemetry/sdk/metrics/metric_reader.h"
 
 #include "opentelemetry/sdk/common/global_log_handler.h"
diff --git a/sdk/src/metrics/metric_reader.cc b/sdk/src/metrics/metric_reader.cc
index a778f0c41c..8b1998fbd3 100644
--- a/sdk/src/metrics/metric_reader.cc
+++ b/sdk/src/metrics/metric_reader.cc
@@ -2,6 +2,7 @@
 // SPDX-License-Identifier: Apache-2.0
 
 #include "opentelemetry/sdk/metrics/metric_reader.h"
+#include "opentelemetry/sdk/common/global_log_handler.h"
 #include "opentelemetry/sdk/metrics/export/metric_producer.h"
 
 #include <mutex>
diff --git a/sdk/src/metrics/state/temporal_metric_storage.cc b/sdk/src/metrics/state/temporal_metric_storage.cc
index 148588ad54..f988551108 100644
--- a/sdk/src/metrics/state/temporal_metric_storage.cc
+++ b/sdk/src/metrics/state/temporal_metric_storage.cc
@@ -1,14 +1,16 @@
 // Copyright The OpenTelemetry Authors
 // SPDX-License-Identifier: Apache-2.0
 
-#include <cstddef>
-#include <memory>
-#include <utility>
-#include "opentelemetry/nostd/shared_ptr.h"
-
+#include "opentelemetry/sdk/metrics/state/temporal_metric_storage.h"
+#include "opentelemetry/common/spin_lock_mutex.h"
 #include "opentelemetry/metrics/meter.h"
 #include "opentelemetry/sdk/metrics/aggregation/default_aggregation.h"
-#include "opentelemetry/sdk/metrics/state/temporal_metric_storage.h"
+#include "opentelemetry/sdk/metrics/state/attributes_hashmap.h"
+#include "opentelemetry/sdk/metrics/state/metric_collector.h"
+
+#include <cstddef>
+#include <mutex>
+#include <utility>
 
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
diff --git a/sdk/src/resource/resource.cc b/sdk/src/resource/resource.cc
index f71e17a8a7..12f8e16d43 100644
--- a/sdk/src/resource/resource.cc
+++ b/sdk/src/resource/resource.cc
@@ -5,6 +5,7 @@
 #include "opentelemetry/nostd/span.h"
 #include "opentelemetry/sdk/resource/resource_detector.h"
 #include "opentelemetry/sdk/resource/semantic_conventions.h"
+#include "opentelemetry/sdk/version/version.h"
 #include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
diff --git a/sdk/src/resource/resource_detector.cc b/sdk/src/resource/resource_detector.cc
index f5c856f088..82e47a71ad 100644
--- a/sdk/src/resource/resource_detector.cc
+++ b/sdk/src/resource/resource_detector.cc
@@ -5,6 +5,9 @@
 #include "opentelemetry/sdk/common/env_variables.h"
 #include "opentelemetry/sdk/resource/resource.h"
 
+#include <sstream>
+#include <string>
+
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
 {
diff --git a/sdk/src/trace/batch_span_processor.cc b/sdk/src/trace/batch_span_processor.cc
index da9f39f054..dd69eaa68f 100644
--- a/sdk/src/trace/batch_span_processor.cc
+++ b/sdk/src/trace/batch_span_processor.cc
@@ -3,9 +3,14 @@
 
 #include "opentelemetry/sdk/trace/batch_span_processor.h"
 #include "opentelemetry/common/spin_lock_mutex.h"
+#include "opentelemetry/common/timestamp.h"
 #include "opentelemetry/sdk/common/global_log_handler.h"
+#include "opentelemetry/sdk/trace/batch_span_processor_options.h"
+#include "opentelemetry/sdk/trace/exporter.h"
+#include "opentelemetry/sdk/trace/recordable.h"
 
 #include <vector>
+
 using opentelemetry::sdk::common::AtomicUniquePtr;
 using opentelemetry::sdk::common::CircularBuffer;
 using opentelemetry::sdk::common::CircularBufferRange;
diff --git a/sdk/src/trace/samplers/parent.cc b/sdk/src/trace/samplers/parent.cc
index 3aa6b4a455..990e1a954a 100644
--- a/sdk/src/trace/samplers/parent.cc
+++ b/sdk/src/trace/samplers/parent.cc
@@ -2,6 +2,7 @@
 // SPDX-License-Identifier: Apache-2.0
 
 #include "opentelemetry/sdk/trace/samplers/parent.h"
+#include "opentelemetry/trace/span_context.h"
 
 namespace trace_api = opentelemetry::trace;
 
diff --git a/sdk/src/trace/span.cc b/sdk/src/trace/span.cc
index 138c966af3..c7524d43aa 100644
--- a/sdk/src/trace/span.cc
+++ b/sdk/src/trace/span.cc
@@ -5,6 +5,8 @@
 #include "src/common/random.h"
 
 #include "opentelemetry/context/runtime_context.h"
+#include "opentelemetry/sdk/trace/recordable.h"
+#include "opentelemetry/trace/span_metadata.h"
 #include "opentelemetry/trace/trace_flags.h"
 #include "opentelemetry/version.h"
 
@@ -48,10 +50,10 @@ SteadyTimestamp NowOr(const SteadyTimestamp &steady)
 Span::Span(std::shared_ptr<Tracer> &&tracer,
            nostd::string_view name,
            const common::KeyValueIterable &attributes,
-           const trace_api::SpanContextKeyValueIterable &links,
-           const trace_api::StartSpanOptions &options,
-           const trace_api::SpanContext &parent_span_context,
-           std::unique_ptr<trace_api::SpanContext> span_context) noexcept
+           const opentelemetry::trace::SpanContextKeyValueIterable &links,
+           const opentelemetry::trace::StartSpanOptions &options,
+           const opentelemetry::trace::SpanContext &parent_span_context,
+           std::unique_ptr<opentelemetry::trace::SpanContext> span_context) noexcept
     : tracer_{std::move(tracer)},
       recordable_{tracer_->GetProcessor().MakeRecordable()},
       start_steady_time{options.start_steady_time},
@@ -66,7 +68,7 @@ Span::Span(std::shared_ptr<Tracer> &&tracer,
   recordable_->SetInstrumentationScope(tracer_->GetInstrumentationScope());
   recordable_->SetIdentity(*span_context_, parent_span_context.IsValid()
                                                ? parent_span_context.span_id()
-                                               : trace_api::SpanId());
+                                               : opentelemetry::trace::SpanId());
 
   attributes.ForEachKeyValue([&](nostd::string_view key, common::AttributeValue value) noexcept {
     recordable_->SetAttribute(key, value);
@@ -164,7 +166,7 @@ void Span::UpdateName(nostd::string_view name) noexcept
   recordable_->SetName(name);
 }
 
-void Span::End(const trace_api::EndSpanOptions &options) noexcept
+void Span::End(const opentelemetry::trace::EndSpanOptions &options) noexcept
 {
   std::lock_guard<std::mutex> lock_guard{mu_};
 
diff --git a/sdk/src/trace/tracer.cc b/sdk/src/trace/tracer.cc
index 07fd36d5b7..6ca7b37df5 100644
--- a/sdk/src/trace/tracer.cc
+++ b/sdk/src/trace/tracer.cc
@@ -3,13 +3,10 @@
 
 #include "opentelemetry/sdk/trace/tracer.h"
 #include "opentelemetry/context/runtime_context.h"
-#include "opentelemetry/nostd/shared_ptr.h"
-#include "opentelemetry/sdk/common/atomic_shared_ptr.h"
 #include "opentelemetry/trace/context.h"
-#include "opentelemetry/version.h"
-#include "src/trace/span.h"
+#include "opentelemetry/trace/noop.h"
 
-#include <memory>
+#include "src/trace/span.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
@@ -17,21 +14,21 @@ namespace sdk
 namespace trace
 {
 
-Tracer::Tracer(std::shared_ptr<sdk::trace::TracerContext> context,
+Tracer::Tracer(std::shared_ptr<TracerContext> context,
                std::unique_ptr<InstrumentationScope> instrumentation_scope) noexcept
     : instrumentation_scope_{std::move(instrumentation_scope)}, context_{context}
 {}
 
-nostd::shared_ptr<trace_api::Span> Tracer::StartSpan(
+nostd::shared_ptr<opentelemetry::trace::Span> Tracer::StartSpan(
     nostd::string_view name,
     const opentelemetry::common::KeyValueIterable &attributes,
-    const trace_api::SpanContextKeyValueIterable &links,
-    const trace_api::StartSpanOptions &options) noexcept
+    const opentelemetry::trace::SpanContextKeyValueIterable &links,
+    const opentelemetry::trace::StartSpanOptions &options) noexcept
 {
-  trace_api::SpanContext parent_context = GetCurrentSpan()->GetContext();
-  if (nostd::holds_alternative<trace_api::SpanContext>(options.parent))
+  opentelemetry::trace::SpanContext parent_context = GetCurrentSpan()->GetContext();
+  if (nostd::holds_alternative<opentelemetry::trace::SpanContext>(options.parent))
   {
-    auto span_context = nostd::get<trace_api::SpanContext>(options.parent);
+    auto span_context = nostd::get<opentelemetry::trace::SpanContext>(options.parent);
     if (span_context.IsValid())
     {
       parent_context = span_context;
@@ -48,9 +45,9 @@ nostd::shared_ptr<trace_api::Span> Tracer::StartSpan(
     }
   }
 
-  trace_api::TraceId trace_id;
-  trace_api::SpanId span_id = GetIdGenerator().GenerateSpanId();
-  bool is_parent_span_valid = false;
+  opentelemetry::trace::TraceId trace_id;
+  opentelemetry::trace::SpanId span_id = GetIdGenerator().GenerateSpanId();
+  bool is_parent_span_valid            = false;
 
   if (parent_context.IsValid())
   {
@@ -64,28 +61,32 @@ nostd::shared_ptr<trace_api::Span> Tracer::StartSpan(
 
   auto sampling_result = context_->GetSampler().ShouldSample(parent_context, trace_id, name,
                                                              options.kind, attributes, links);
-  auto trace_flags     = sampling_result.IsSampled()
-                         ? trace_api::TraceFlags{trace_api::TraceFlags::kIsSampled}
-                         : trace_api::TraceFlags{};
-
-  auto span_context = std::unique_ptr<trace_api::SpanContext>(new trace_api::SpanContext(
-      trace_id, span_id, trace_flags, false,
-      sampling_result.trace_state ? sampling_result.trace_state
-                                  : is_parent_span_valid ? parent_context.trace_state()
-                                                         : trace_api::TraceState::GetDefault()));
+  auto trace_flags =
+      sampling_result.IsSampled()
+          ? opentelemetry::trace::TraceFlags{opentelemetry::trace::TraceFlags::kIsSampled}
+          : opentelemetry::trace::TraceFlags{};
+
+  auto span_context =
+      std::unique_ptr<opentelemetry::trace::SpanContext>(new opentelemetry::trace::SpanContext(
+          trace_id, span_id, trace_flags, false,
+          sampling_result.trace_state
+              ? sampling_result.trace_state
+              : is_parent_span_valid ? parent_context.trace_state()
+                                     : opentelemetry::trace::TraceState::GetDefault()));
 
   if (!sampling_result.IsRecording())
   {
     // create no-op span with valid span-context.
 
-    auto noop_span = nostd::shared_ptr<trace_api::Span>{
-        new (std::nothrow) trace_api::NoopSpan(this->shared_from_this(), std::move(span_context))};
+    auto noop_span = nostd::shared_ptr<opentelemetry::trace::Span>{
+        new (std::nothrow)
+            opentelemetry::trace::NoopSpan(this->shared_from_this(), std::move(span_context))};
     return noop_span;
   }
   else
   {
 
-    auto span = nostd::shared_ptr<trace_api::Span>{
+    auto span = nostd::shared_ptr<opentelemetry::trace::Span>{
         new (std::nothrow) Span{this->shared_from_this(), name, attributes, links, options,
                                 parent_context, std::move(span_context)}};
 
diff --git a/sdk/src/trace/tracer_provider.cc b/sdk/src/trace/tracer_provider.cc
index b5eed6312f..7ac66ed6db 100644
--- a/sdk/src/trace/tracer_provider.cc
+++ b/sdk/src/trace/tracer_provider.cc
@@ -3,6 +3,9 @@
 
 #include "opentelemetry/sdk/trace/tracer_provider.h"
 #include "opentelemetry/sdk/common/global_log_handler.h"
+#include "opentelemetry/sdk/trace/processor.h"
+#include "opentelemetry/sdk/trace/tracer.h"
+#include "opentelemetry/sdk/trace/tracer_context.h"
 #include "opentelemetry/sdk_config.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE
diff --git a/sdk/src/trace/tracer_provider_factory.cc b/sdk/src/trace/tracer_provider_factory.cc
index df25694781..158ae949ea 100644
--- a/sdk/src/trace/tracer_provider_factory.cc
+++ b/sdk/src/trace/tracer_provider_factory.cc
@@ -2,6 +2,7 @@
 // SPDX-License-Identifier: Apache-2.0
 
 #include "opentelemetry/sdk/trace/tracer_provider_factory.h"
+#include "opentelemetry/sdk/trace/processor.h"
 #include "opentelemetry/sdk/trace/random_id_generator_factory.h"
 #include "opentelemetry/sdk/trace/samplers/always_on_factory.h"
 #include "opentelemetry/sdk/trace/tracer_provider.h"
diff --git a/sdk/test/logs/log_record_test.cc b/sdk/test/logs/log_record_test.cc
index cce81d9910..0e5de03050 100644
--- a/sdk/test/logs/log_record_test.cc
+++ b/sdk/test/logs/log_record_test.cc
@@ -12,6 +12,7 @@
 #  include "opentelemetry/logs/provider.h"
 #  include "opentelemetry/nostd/variant.h"
 #  include "opentelemetry/sdk/logs/read_write_log_record.h"
+#  include "opentelemetry/sdk/resource/resource.h"
 #  include "opentelemetry/trace/span_id.h"
 #  include "opentelemetry/trace/trace_id.h"
 
diff --git a/sdk/test/logs/logger_provider_sdk_test.cc b/sdk/test/logs/logger_provider_sdk_test.cc
index 510f02b4df..e9bc897745 100644
--- a/sdk/test/logs/logger_provider_sdk_test.cc
+++ b/sdk/test/logs/logger_provider_sdk_test.cc
@@ -10,6 +10,7 @@
 #  include "opentelemetry/nostd/shared_ptr.h"
 #  include "opentelemetry/nostd/string_view.h"
 #  include "opentelemetry/sdk/logs/event_logger_provider_factory.h"
+#  include "opentelemetry/sdk/logs/exporter.h"
 #  include "opentelemetry/sdk/logs/logger.h"
 #  include "opentelemetry/sdk/logs/logger_provider.h"
 #  include "opentelemetry/sdk/logs/recordable.h"
diff --git a/sdk/test/logs/logger_sdk_test.cc b/sdk/test/logs/logger_sdk_test.cc
index 0e5050a973..66f9edb8c5 100644
--- a/sdk/test/logs/logger_sdk_test.cc
+++ b/sdk/test/logs/logger_sdk_test.cc
@@ -6,12 +6,16 @@
 #  include <chrono>
 #  include <string>
 
+#  include "opentelemetry/logs/logger_provider.h"
 #  include "opentelemetry/nostd/string_view.h"
-#  include "opentelemetry/nostd/variant.h"
 #  include "opentelemetry/sdk/logs/event_logger.h"
 #  include "opentelemetry/sdk/logs/event_logger_provider.h"
 #  include "opentelemetry/sdk/logs/logger.h"
+#  include "opentelemetry/sdk/logs/logger_provider.h"
+#  include "opentelemetry/sdk/logs/processor.h"
 #  include "opentelemetry/sdk/logs/recordable.h"
+#  include "opentelemetry/sdk/trace/processor.h"
+#  include "opentelemetry/sdk/trace/tracer_provider.h"
 #  include "opentelemetry/sdk/trace/tracer_provider_factory.h"
 #  include "opentelemetry/trace/scope.h"
 #  include "opentelemetry/trace/tracer.h"
diff --git a/sdk/test/metrics/aggregation_test.cc b/sdk/test/metrics/aggregation_test.cc
index 9f307cb015..94e5f4c1fa 100644
--- a/sdk/test/metrics/aggregation_test.cc
+++ b/sdk/test/metrics/aggregation_test.cc
@@ -2,6 +2,7 @@
 // SPDX-License-Identifier: Apache-2.0
 
 #include <gtest/gtest.h>
+#include "opentelemetry/sdk/metrics/aggregation/aggregation_config.h"
 #include "opentelemetry/sdk/metrics/aggregation/histogram_aggregation.h"
 #include "opentelemetry/sdk/metrics/aggregation/lastvalue_aggregation.h"
 #include "opentelemetry/sdk/metrics/aggregation/sum_aggregation.h"
diff --git a/sdk/test/metrics/async_instruments_test.cc b/sdk/test/metrics/async_instruments_test.cc
index 87d0a441d5..10c0335559 100644
--- a/sdk/test/metrics/async_instruments_test.cc
+++ b/sdk/test/metrics/async_instruments_test.cc
@@ -3,6 +3,7 @@
 
 #include "opentelemetry/sdk/metrics/async_instruments.h"
 #include "opentelemetry/sdk/metrics/state/multi_metric_storage.h"
+#include "opentelemetry/sdk/metrics/state/observable_registry.h"
 
 #include <gtest/gtest.h>
 
diff --git a/sdk/test/metrics/attributes_hashmap_benchmark.cc b/sdk/test/metrics/attributes_hashmap_benchmark.cc
index f0286ec09e..0568080a6d 100644
--- a/sdk/test/metrics/attributes_hashmap_benchmark.cc
+++ b/sdk/test/metrics/attributes_hashmap_benchmark.cc
@@ -9,6 +9,8 @@
 #include "opentelemetry/sdk/metrics/state/attributes_hashmap.h"
 
 #include <functional>
+#include <mutex>
+#include <thread>
 #include <vector>
 
 using namespace opentelemetry::sdk::metrics;
diff --git a/sdk/test/metrics/exemplar/always_sample_filter_test.cc b/sdk/test/metrics/exemplar/always_sample_filter_test.cc
index cd9e58f284..30c86fd37f 100644
--- a/sdk/test/metrics/exemplar/always_sample_filter_test.cc
+++ b/sdk/test/metrics/exemplar/always_sample_filter_test.cc
@@ -2,6 +2,8 @@
 // SPDX-License-Identifier: Apache-2.0
 
 #include <gtest/gtest.h>
+
+#include "opentelemetry/context/context.h"
 #include "opentelemetry/sdk/metrics/exemplar/filter.h"
 
 using namespace opentelemetry::sdk::metrics;
diff --git a/sdk/test/metrics/multi_metric_storage_test.cc b/sdk/test/metrics/multi_metric_storage_test.cc
index 1c230bafcf..e7e4151f09 100644
--- a/sdk/test/metrics/multi_metric_storage_test.cc
+++ b/sdk/test/metrics/multi_metric_storage_test.cc
@@ -9,7 +9,6 @@
 #include <gtest/gtest.h>
 
 using namespace opentelemetry;
-using namespace opentelemetry::sdk::instrumentationscope;
 using namespace opentelemetry::sdk::metrics;
 
 class TestMetricStorage : public SyncWritableMetricStorage
diff --git a/sdk/test/resource/resource_test.cc b/sdk/test/resource/resource_test.cc
index 803d5666d9..96de75c04a 100644
--- a/sdk/test/resource/resource_test.cc
+++ b/sdk/test/resource/resource_test.cc
@@ -2,15 +2,14 @@
 // SPDX-License-Identifier: Apache-2.0
 
 #include "opentelemetry/sdk/resource/resource.h"
-#include "opentelemetry/common/key_value_iterable_view.h"
-#include "opentelemetry/nostd/string_view.h"
 #include "opentelemetry/sdk/common/attribute_utils.h"
 #include "opentelemetry/sdk/resource/resource_detector.h"
 #include "opentelemetry/sdk/resource/semantic_conventions.h"
+#include "opentelemetry/sdk/version/version.h"
 
 #include <cstdlib>
+#include <map>
 #include <string>
-#include <unordered_map>
 
 #include <gtest/gtest.h>
 
diff --git a/sdk/test/trace/batch_span_processor_test.cc b/sdk/test/trace/batch_span_processor_test.cc
index b7a6558538..411b4dacfe 100644
--- a/sdk/test/trace/batch_span_processor_test.cc
+++ b/sdk/test/trace/batch_span_processor_test.cc
@@ -2,11 +2,15 @@
 // SPDX-License-Identifier: Apache-2.0
 
 #include "opentelemetry/sdk/trace/batch_span_processor.h"
+#include "opentelemetry/sdk/common/exporter_utils.h"
 #include "opentelemetry/sdk/common/global_log_handler.h"
+#include "opentelemetry/sdk/trace/batch_span_processor_options.h"
+#include "opentelemetry/sdk/trace/exporter.h"
 #include "opentelemetry/sdk/trace/span_data.h"
 #include "opentelemetry/sdk/trace/tracer.h"
 
 #include <gtest/gtest.h>
+
 #include <algorithm>
 #include <chrono>
 #include <list>
diff --git a/sdk/test/trace/sampler_benchmark.cc b/sdk/test/trace/sampler_benchmark.cc
index 17999dcf26..42de190980 100644
--- a/sdk/test/trace/sampler_benchmark.cc
+++ b/sdk/test/trace/sampler_benchmark.cc
@@ -69,11 +69,13 @@ void BenchmarkShouldSampler(Sampler &sampler, benchmark::State &state)
   using M = std::map<std::string, int>;
   M m1    = {{}};
 
-  using L = std::vector<std::pair<trace_api::SpanContext, std::map<std::string, std::string>>>;
-  L l1 = {{trace_api::SpanContext(false, false), {}}, {trace_api::SpanContext(false, false), {}}};
+  using L =
+      std::vector<std::pair<opentelemetry::trace::SpanContext, std::map<std::string, std::string>>>;
+  L l1 = {{opentelemetry::trace::SpanContext(false, false), {}},
+          {opentelemetry::trace::SpanContext(false, false), {}}};
 
   opentelemetry::common::KeyValueIterableView<M> view{m1};
-  trace_api::SpanContextKeyValueIterableView<L> links{l1};
+  opentelemetry::trace::SpanContextKeyValueIterableView<L> links{l1};
 
   while (state.KeepRunning())
   {
diff --git a/sdk/test/trace/tracer_test.cc b/sdk/test/trace/tracer_test.cc
index f92c0f6e93..45b5fc010f 100644
--- a/sdk/test/trace/tracer_test.cc
+++ b/sdk/test/trace/tracer_test.cc
@@ -17,8 +17,9 @@ using namespace opentelemetry::sdk::trace;
 using namespace opentelemetry::sdk::resource;
 using opentelemetry::common::SteadyTimestamp;
 using opentelemetry::common::SystemTimestamp;
-namespace nostd  = opentelemetry::nostd;
-namespace common = opentelemetry::common;
+namespace nostd     = opentelemetry::nostd;
+namespace common    = opentelemetry::common;
+namespace trace_api = opentelemetry::trace;
 using opentelemetry::common::KeyValueIterableView;
 using opentelemetry::exporter::memory::InMemorySpanData;
 using opentelemetry::exporter::memory::InMemorySpanExporter;

From bbe9ddf4cfef7b1791013dbf5e56686a0d29e5f7 Mon Sep 17 00:00:00 2001
From: Cengizhan Pasaoglu <cengizhanpasaoglu@gmail.com>
Date: Tue, 13 Jun 2023 15:01:15 +0200
Subject: [PATCH 2/2] Include a few header files additionally after code review
 comments

---
 examples/jaeger/main.cc        | 1 +
 examples/otlp/grpc_log_main.cc | 2 ++
 2 files changed, 3 insertions(+)

diff --git a/examples/jaeger/main.cc b/examples/jaeger/main.cc
index 1b60eaed2a..a5b3c38c35 100644
--- a/examples/jaeger/main.cc
+++ b/examples/jaeger/main.cc
@@ -2,6 +2,7 @@
 // SPDX-License-Identifier: Apache-2.0
 
 #include "opentelemetry/exporters/jaeger/jaeger_exporter_factory.h"
+#include "opentelemetry/sdk/trace/exporter.h"
 #include "opentelemetry/sdk/trace/processor.h"
 #include "opentelemetry/sdk/trace/simple_processor_factory.h"
 #include "opentelemetry/sdk/trace/tracer_provider_factory.h"
diff --git a/examples/otlp/grpc_log_main.cc b/examples/otlp/grpc_log_main.cc
index ffd4376ebf..f6f6685922 100644
--- a/examples/otlp/grpc_log_main.cc
+++ b/examples/otlp/grpc_log_main.cc
@@ -5,9 +5,11 @@
 #  include "opentelemetry/exporters/otlp/otlp_grpc_exporter_factory.h"
 #  include "opentelemetry/exporters/otlp/otlp_grpc_log_record_exporter_factory.h"
 #  include "opentelemetry/logs/provider.h"
+#  include "opentelemetry/sdk/logs/exporter.h"
 #  include "opentelemetry/sdk/logs/logger_provider_factory.h"
 #  include "opentelemetry/sdk/logs/processor.h"
 #  include "opentelemetry/sdk/logs/simple_log_record_processor_factory.h"
+#  include "opentelemetry/sdk/trace/exporter.h"
 #  include "opentelemetry/sdk/trace/processor.h"
 #  include "opentelemetry/sdk/trace/simple_processor_factory.h"
 #  include "opentelemetry/sdk/trace/tracer_provider_factory.h"