diff --git a/Makefile b/Makefile
index 36dbcf2..cd0fc0e 100644
--- a/Makefile
+++ b/Makefile
@@ -33,6 +33,10 @@ test-client: test-client-p256 test-client-ed25519
 test-client-p256: test-private-p256.pem
 	openssl rand 1024 > random.bin
 	poetry run aggrec_client --http-key-id test-p256 --http-key-file $< random.bin
+	openssl rand 1024 > random.bin
+	poetry run aggrec_client --http-key-id test-p256 --http-key-file $< random.bin
+	poetry run aggrec_client --http-key-id test-p256 --http-key-file $< random.bin
+	poetry run aggrec_client --http-key-id test-p256 --http-key-file $< random.bin
 
 test-client-ed25519: test-private-ed25519.pem
 	openssl rand 1024 > random.bin
diff --git a/aggrec/aggregates.py b/aggrec/aggregates.py
index c811590..48fa39d 100644
--- a/aggrec/aggregates.py
+++ b/aggrec/aggregates.py
@@ -31,6 +31,16 @@
     description="The number of aggregates stored",
 )
 
+aggregates_by_creator_counter = meter.create_counter(
+    "aggregates.counter_by_creator",
+    description="The number of aggregates per creator",
+)
+
+aggregates_duplicates_counter = meter.create_counter(
+    "aggregates.duplicates_counter",
+    description="The number of duplicate aggregates received",
+)
+
 
 METADATA_HTTP_HEADERS = [
     "User-Agent",
@@ -107,6 +117,11 @@ def get_http_headers(request: Request, covered_components_headers: List[str]) ->
     return res
 
 
+def get_aggregate_location(aggregate_id: ObjectId) -> str:
+    """Get aggregate location"""
+    return f"/api/v1/aggregates/{aggregate_id}"
+
+
 def get_new_aggregate_event_message(metadata: AggregateMetadata, settings: Settings) -> dict:
     """Get new aggregate event message"""
     return {
@@ -246,8 +261,15 @@ async def create_aggregate(
 
     http_headers = get_http_headers(request, res.covered_components.keys())
 
+    # if we receive an aggregate already seen, return existing metadata
+    if metadata := AggregateMetadata.objects(content_digest=content_digest).first():
+        logger.warning("Received duplicate aggregate from %s", creator)
+        aggregates_duplicates_counter.add(1, {"aggregate_type": aggregate_type.value, "creator": creator})
+        metadata_location = get_aggregate_location(metadata.id)
+        return Response(status_code=status.HTTP_201_CREATED, headers={"Location": metadata_location})
+
     aggregate_id = ObjectId()
-    location = f"/api/v1/aggregates/{aggregate_id}"
+    metadata_location = get_aggregate_location(aggregate_id)
 
     span.set_attribute("aggregate.id", str(aggregate_id))
     span.set_attribute("aggregate.type", aggregate_type.value)
@@ -273,6 +295,7 @@ async def create_aggregate(
         creator=creator,
         http_headers=http_headers,
         content_type=content_type,
+        content_digest=content_digest,
         s3_bucket=s3_bucket,
     )
 
@@ -304,6 +327,7 @@ async def create_aggregate(
     logger.info("Metadata saved: %s", metadata.id)
 
     aggregates_counter.add(1, {"aggregate_type": aggregate_type.value})
+    aggregates_by_creator_counter.add(1, {"aggregate_type": aggregate_type.value, "creator": creator})
 
     async with request.app.get_mqtt_client() as mqtt_client:
         with tracer.start_as_current_span("mqtt.publish"):
@@ -312,7 +336,7 @@ async def create_aggregate(
                 json.dumps(get_new_aggregate_event_message(metadata, request.app.settings)),
             )
 
-    return Response(status_code=status.HTTP_201_CREATED, headers={"Location": location})
+    return Response(status_code=status.HTTP_201_CREATED, headers={"Location": metadata_location})
 
 
 @router.get(
@@ -372,7 +396,7 @@ async def get_aggregate_payload(
             async with request.app.get_s3_client() as s3_client:
                 s3_obj = await s3_client.get_object(Bucket=metadata.s3_bucket, Key=metadata.s3_object_key)
 
-        metadata_location = f"/api/v1/aggregates/{aggregate_id}"
+        metadata_location = get_aggregate_location(metadata.id)
 
         return StreamingResponse(
             content=s3_obj["Body"],
diff --git a/aggrec/db_models.py b/aggrec/db_models.py
index 2e8045b..794aa8f 100644
--- a/aggrec/db_models.py
+++ b/aggrec/db_models.py
@@ -19,6 +19,7 @@ class AggregateMetadata(Document):
 
     content_type = StringField()
     content_length = IntField()
+    content_digest = StringField(unique=True, sparse=True)
 
     s3_bucket = StringField()
     s3_object_key = StringField()