diff --git a/build.gradle.kts b/build.gradle.kts
index e71787a..5080366 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -60,6 +60,12 @@ dependencies {
     api("io.micrometer:micrometer-core:$micrometerVersion")
     api("io.micrometer:micrometer-registry-prometheus:$micrometerVersion")
 
+    val cosmosSdkVersion = "1.0-SNAPSHOT"
+    implementation("com.okp4.grpc:cosmos-sdk:$cosmosSdkVersion")
+
+    val grpcVersion = "1.45.1"
+    api("io.grpc:grpc-protobuf:$grpcVersion")
+
     testImplementation(kotlin("test"))
 
     val kotestVersion = "5.2.1"
diff --git a/src/main/kotlin/com/okp4/processor/cosmos/topology.kt b/src/main/kotlin/com/okp4/processor/cosmos/topology.kt
index 8a5dbb0..c70cd44 100644
--- a/src/main/kotlin/com/okp4/processor/cosmos/topology.kt
+++ b/src/main/kotlin/com/okp4/processor/cosmos/topology.kt
@@ -1,17 +1,18 @@
 package com.okp4.processor.cosmos
 
+import cosmos.tx.v1beta1.TxOuterClass
 import org.apache.kafka.common.serialization.Serdes
-import org.apache.kafka.streams.KeyValue
 import org.apache.kafka.streams.StreamsBuilder
 import org.apache.kafka.streams.Topology
 import org.apache.kafka.streams.kstream.Consumed
 import org.apache.kafka.streams.kstream.Named
 import org.apache.kafka.streams.kstream.Produced
 import org.slf4j.LoggerFactory
+import tendermint.types.BlockOuterClass
 import java.util.*
 
 /**
- * Simple Kafka Stream Processor that consumes a message on a topic and returns a new message on another.
+ * Simple Kafka Stream Processor that consumes a block on a topic and returns his transactions on another.
  */
 fun topology(props: Properties): Topology {
     val logger = LoggerFactory.getLogger("com.okp4.processor.cosmos.topology")
@@ -24,9 +25,10 @@ fun topology(props: Properties): Topology {
 
     return StreamsBuilder()
         .apply {
-            stream(topicIn, Consumed.with(Serdes.String(), Serdes.String()).withName("input"))
-                .peek({ _, _ -> logger.info("Received a message") }, Named.`as`("log"))
-                .map({ k, v -> KeyValue(k, "Hello $v!") }, Named.`as`("map-value"))
-                .to(topicOut, Produced.with(Serdes.String(), Serdes.String()).withName("output"))
+            stream(topicIn, Consumed.with(Serdes.String(), Serdes.ByteArray()).withName("input"))
+                .mapValues({ v -> BlockOuterClass.Block.parseFrom(v) }, Named.`as`("block-deserialization"))
+                .peek({ _, block -> logger.debug("→ block ${block.header.height} (${block.data.txsCount} txs)") }, Named.`as`("log"))
+                .flatMapValues({ block -> block.data.txsList.map { tx -> TxOuterClass.Tx.parseFrom(tx).toByteArray() } }, Named.`as`("extract-transactions"))
+                .to(topicOut, Produced.with(Serdes.String(), Serdes.ByteArray()).withName("output"))
         }.build()
 }