diff --git a/routemaster/conftest.py b/routemaster/conftest.py
index 76804c58..50b78503 100644
--- a/routemaster/conftest.py
+++ b/routemaster/conftest.py
@@ -326,7 +326,7 @@ def database_clear(app: TestApp) -> Iterator[None]:
         with app.new_session():
             for table in metadata.tables:
                 app.session.execute(
-                    f'truncate table {table} cascade',
+                    f'truncate table {table} cascade',  # type: ignore[arg-type]  # noqa: E501
                     {},
                 )
 
@@ -514,8 +514,7 @@ def _inner(label: LabelRef) -> str:
                 label_name=label.name,
                 label_state_machine=label.state_machine,
             ).order_by(
-                # TODO: use the sqlalchemy mypy plugin rather than our stubs
-                History.id.desc(),  # type: ignore[attr-defined]
+                History.id.desc(),
             ).limit(1).scalar()
     return _inner
 
diff --git a/routemaster/db/model.py b/routemaster/db/model.py
index 9c52be81..919600f6 100644
--- a/routemaster/db/model.py
+++ b/routemaster/db/model.py
@@ -1,7 +1,7 @@
 """Database model definition."""
 import datetime
 import functools
-from typing import Any
+from typing import Any, Dict, List, Optional
 
 import dateutil.tz
 from sqlalchemy import DDL, Table
@@ -16,7 +16,7 @@
     ForeignKeyConstraint,
     func,
 )
-from sqlalchemy.orm import relationship
+from sqlalchemy.orm import Mapped, relationship
 from sqlalchemy.ext.declarative import declarative_base
 from sqlalchemy.dialects.postgresql import JSONB
 
@@ -53,7 +53,8 @@
 class Label(Base):
     """A single label including context."""
 
-    # Note: type annotations for this class are provided by a stubs file
+    # Note: type annotations provided below must be manually kept in sync with
+    # the fields defined in the Table.
 
     __table__ = Table(
         'labels',
@@ -74,6 +75,15 @@ class Label(Base):
         ],
     )
 
+    name: Mapped[str]
+    state_machine: Mapped[str]
+    metadata: Mapped[Dict[str, Any]]
+    metadata_triggers_processed: Mapped[bool]
+    deleted: Mapped[bool]
+    updated: Mapped[datetime.datetime]
+
+    history: List['History'] = relationship('History')
+
     def __repr__(self) -> str:
         """Return a useful debug representation."""
         return (
@@ -84,7 +94,8 @@ def __repr__(self) -> str:
 class History(Base):
     """A single historical state transition of a label."""
 
-    # Note: type annotations for this class are provided by a stubs file
+    # Note: type annotations provided below must be manually kept in sync with
+    # the fields defined in the Table.
 
     __table__ = Table(
         'history',
@@ -115,7 +126,15 @@ class History(Base):
         NullableColumn('new_state', String),
     )
 
-    label = relationship(Label, backref='history')
+    id: Mapped[int]
+    label_name: Mapped[str]
+    label_state_machine: Mapped[str]
+    created: Mapped[datetime.datetime]
+    forced: Mapped[bool]
+    old_state: Mapped[Optional[str]]
+    new_state: Mapped[Optional[str]]
+
+    label: Label = relationship(Label)
 
     def __repr__(self) -> str:
         """Return a useful debug representation."""
diff --git a/routemaster/db/model.pyi b/routemaster/db/model.pyi
deleted file mode 100644
index 6f108bc1..00000000
--- a/routemaster/db/model.pyi
+++ /dev/null
@@ -1,60 +0,0 @@
-import datetime
-from typing import Any, Dict, List, Union, Optional
-
-from sqlalchemy import MetaData
-
-# Imperfect JSON type (see https://github.com/python/typing/issues/182)
-_JSON = Union[str, int, float, bool, None, Dict[str, Any], List[Any]]
-
-
-metadata: MetaData
-
-
-class Label:
-    name: str
-    state_machine: str
-    metadata: _JSON
-    metadata_triggers_processed: bool
-    deleted: bool
-    updated: datetime.datetime
-
-    history: List['History']
-
-    def __init__(
-        self,
-        *,
-        name: str = ...,
-        state_machine: str = ...,
-        metadata: _JSON = ...,
-        metadata_triggers_processed: bool = ...,
-        deleted: bool = ...,
-        updated: datetime.datetime = ...,
-        history: List['History'] = ...,
-    ) -> None: ...
-
-
-class History:
-    id: int
-
-    label_name: str
-    label_state_machine: str
-    created: datetime.datetime
-    forced: bool
-
-    old_state: Optional[str]
-    new_state: Optional[str]
-
-    label: Label
-
-    def __init__(
-        self,
-        *,
-        id: int = ...,
-        label_name: str = ...,
-        label_state_machine: str = ...,
-        created: datetime.datetime = ...,
-        forced: bool = ...,
-        old_state: Optional[str] = ...,
-        new_state: Optional[str] = ...,
-        label: Label = ...,
-    ) -> None: ...
diff --git a/routemaster/state_machine/actions.py b/routemaster/state_machine/actions.py
index 0b11a71d..eea1fcae 100644
--- a/routemaster/state_machine/actions.py
+++ b/routemaster/state_machine/actions.py
@@ -16,7 +16,6 @@
     get_label_metadata,
     get_current_history,
 )
-from routemaster.state_machine.exceptions import DeletedLabel
 
 
 def process_action(
@@ -42,9 +41,7 @@ def process_action(
 
     action = state
 
-    metadata, deleted = get_label_metadata(app, label, state_machine)
-    if deleted:
-        raise DeletedLabel(label)
+    metadata = get_label_metadata(app, label)
 
     latest_history = get_current_history(app, label)
 
diff --git a/routemaster/state_machine/api.py b/routemaster/state_machine/api.py
index 4fa9f37b..9a532f7b 100644
--- a/routemaster/state_machine/api.py
+++ b/routemaster/state_machine/api.py
@@ -9,15 +9,11 @@
 from routemaster.config import Gate, State, StateMachine
 from routemaster.state_machine.gates import process_gate
 from routemaster.state_machine.types import LabelRef, Metadata
-from routemaster.state_machine.utils import (
+from routemaster.state_machine.utils import (  # noqa: F401  # re-export
     lock_label,
     get_current_state,
     get_state_machine,
-)
-from routemaster.state_machine.utils import (
-    get_label_metadata as get_label_metadata_internal,
-)
-from routemaster.state_machine.utils import (
+    get_label_metadata,
     needs_gate_evaluation_for_metadata_change,
 )
 from routemaster.state_machine.exceptions import (
@@ -53,23 +49,6 @@ def get_label_state(app: App, label: LabelRef) -> Optional[State]:
     return get_current_state(app, label, state_machine)
 
 
-def get_label_metadata(app: App, label: LabelRef) -> Metadata:
-    """Returns the metadata associated with a label."""
-    state_machine = get_state_machine(app, label)
-
-    row = get_label_metadata_internal(app, label, state_machine)
-
-    if row is None:
-        raise UnknownLabel(label)
-
-    metadata, deleted = row
-
-    if deleted:
-        raise DeletedLabel(label)
-
-    return metadata
-
-
 def create_label(app: App, label: LabelRef, metadata: Metadata) -> Metadata:
     """Creates a label and starts it in a state machine."""
     state_machine = get_state_machine(app, label)
@@ -129,7 +108,7 @@ def update_metadata_for_label(
         )
 
     # FIXME: handle cases where metadata aren't dicts.
-    new_metadata = dict_merge(existing_metadata, update)  # type: ignore[arg-type]  # noqa: E501
+    new_metadata = dict_merge(existing_metadata, update)
 
     row.metadata = new_metadata
     row.metadata_triggers_processed = not needs_gate_evaluation
diff --git a/routemaster/state_machine/gates.py b/routemaster/state_machine/gates.py
index 53ac3ab2..91631a1b 100644
--- a/routemaster/state_machine/gates.py
+++ b/routemaster/state_machine/gates.py
@@ -6,11 +6,9 @@
 from routemaster.state_machine.utils import (
     choose_next_state,
     context_for_label,
-    get_state_machine,
     get_label_metadata,
     get_current_history,
 )
-from routemaster.state_machine.exceptions import DeletedLabel
 
 
 def process_gate(
@@ -36,10 +34,7 @@ def process_gate(
 
     gate = state
 
-    state_machine = get_state_machine(app, label)
-    metadata, deleted = get_label_metadata(app, label, state_machine)
-    if deleted:
-        raise DeletedLabel(label)
+    metadata = get_label_metadata(app, label)
 
     history_entry = get_current_history(app, label)
 
diff --git a/routemaster/state_machine/tests/test_state_machine.py b/routemaster/state_machine/tests/test_state_machine.py
index 94c14468..4089607d 100644
--- a/routemaster/state_machine/tests/test_state_machine.py
+++ b/routemaster/state_machine/tests/test_state_machine.py
@@ -276,7 +276,8 @@ def test_maintains_updated_field_on_label(app, mock_test_feed):
 
 def test_continues_after_time_since_entering_gate(app, current_state):
     label = LabelRef('foo', 'test_machine_timing')
-    gate = app.config.state_machines['test_machine_timing'].states[0]
+    test_machine = app.config.state_machines['test_machine_timing']
+    gate = test_machine.states[0]
 
     with freeze_time('2018-01-24 12:00:00'), app.new_session():
         state_machine.create_label(
@@ -290,7 +291,7 @@ def test_continues_after_time_since_entering_gate(app, current_state):
         process_gate(
             app=app,
             state=gate,
-            state_machine=state_machine,
+            state_machine=test_machine,
             label=label,
         )
 
@@ -301,7 +302,7 @@ def test_continues_after_time_since_entering_gate(app, current_state):
         process_gate(
             app=app,
             state=gate,
-            state_machine=state_machine,
+            state_machine=test_machine,
             label=label,
         )
 
diff --git a/routemaster/state_machine/utils.py b/routemaster/state_machine/utils.py
index ccf2fc73..410a13ce 100644
--- a/routemaster/state_machine/utils.py
+++ b/routemaster/state_machine/utils.py
@@ -27,6 +27,7 @@
 from routemaster.logging import BaseLogger
 from routemaster.state_machine.types import LabelRef, Metadata
 from routemaster.state_machine.exceptions import (
+    DeletedLabel,
     UnknownLabel,
     UnknownStateMachine,
 )
@@ -52,11 +53,11 @@ def choose_next_state(
     return state_machine.get_state(next_state_name)
 
 
-def get_label_metadata(
+def _get_label_metadata(
     app: App,
     label: LabelRef,
     state_machine: StateMachine,
-) -> Tuple[Dict[str, Any], bool]:
+) -> Optional[Tuple[Dict[str, Any], bool]]:
     """Get the metadata and whether the label has been deleted."""
     return app.session.query(Label.metadata, Label.deleted).filter_by(
         name=label.name,
@@ -64,6 +65,23 @@ def get_label_metadata(
     ).first()
 
 
+def get_label_metadata(app: App, label: LabelRef) -> Metadata:
+    """Returns the metadata associated with a label."""
+    state_machine = get_state_machine(app, label)
+
+    row = _get_label_metadata(app, label, state_machine)
+
+    if row is None:
+        raise UnknownLabel(label)
+
+    metadata, deleted = row
+
+    if deleted:
+        raise DeletedLabel(label)
+
+    return metadata
+
+
 def get_current_state(
     app: App,
     label: LabelRef,
@@ -83,11 +101,7 @@ def get_current_history(app: App, label: LabelRef) -> History:
         label_name=label.name,
         label_state_machine=label.state_machine,
     ).order_by(
-        # Our model type stubs define the `id` attribute as `int`, yet
-        # sqlalchemy actually allows the attribute to be used for ordering like
-        # this; ignore the type check here specifically rather than complicate
-        # our type definitions.
-        History.id.desc(),  # type: ignore[attr-defined]
+        History.id.desc(),
     ).first()
 
     if history_entry is None:
@@ -167,14 +181,13 @@ def labels_in_state_with_metadata(
 
     metadata_lookup = Label.metadata
     for part in path:
-        metadata_lookup = metadata_lookup[part]  # type: ignore[call-overload, index]  # noqa: E501
+        metadata_lookup = metadata_lookup[part]  # type: ignore[assignment]  # noqa: E501
 
     return _labels_in_state(
         app,
         state_machine,
         state,
-        # TODO: use the sqlalchemy mypy plugin rather than our stubs file
-        metadata_lookup.astext.in_(values),  # type: ignore[union-attr]
+        metadata_lookup.astext.in_(values),
     )
 
 
@@ -210,11 +223,7 @@ def _labels_in_state(
         History.label_name,
         History.new_state,
         func.row_number().over(
-            # Our model type stubs define the `id` attribute as `int`, yet
-            # sqlalchemy actually allows the attribute to be used for ordering
-            # like this; ignore the type check here specifically rather than
-            # complicate our type definitions.
-            order_by=History.id.desc(),  # type: ignore[attr-defined]
+            order_by=History.id.desc(),
             partition_by=History.label_name,
         ).label('rank'),
     ).filter_by(
diff --git a/routemaster/validation.py b/routemaster/validation.py
index 7efff465..83b72246 100644
--- a/routemaster/validation.py
+++ b/routemaster/validation.py
@@ -78,8 +78,7 @@ def _validate_no_labels_in_nonexistent_states(
         History.label_name,
         History.new_state,
         func.row_number().over(
-            # TODO: use the sqlalchemy mypy plugin rather than our stubs file
-            order_by=History.id.desc(),  # type: ignore[attr-defined]
+            order_by=History.id.desc(),
             partition_by=History.label_name,
         ).label('rank'),
     ).filter_by(
diff --git a/setup.cfg b/setup.cfg
index 0c94fe5e..782e94e9 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -18,6 +18,7 @@ strict_optional=true
 show_error_codes = true
 enable_error_code = ignore-without-code
 warn_unused_ignores = true
+plugins = sqlalchemy.ext.mypy.plugin
 
 [coverage:run]
 branch=True
diff --git a/setup.py b/setup.py
index e6c129e7..fb5ec3f3 100644
--- a/setup.py
+++ b/setup.py
@@ -50,7 +50,7 @@
         'jsonschema >=3, <5',
         'flask',
         'psycopg2-binary',
-        'sqlalchemy',
+        'sqlalchemy[mypy]',
         'python-dateutil',
         'alembic >=0.9.6',
         'gunicorn >=19.7',