diff --git a/codebase/backend/api-backend/alembic/versions/0010_contact_map_dedup.py b/codebase/backend/api-backend/alembic/versions/0010_contact_map_dedup.py
new file mode 100644
index 0000000..8a21e5a
--- /dev/null
+++ b/codebase/backend/api-backend/alembic/versions/0010_contact_map_dedup.py
@@ -0,0 +1,75 @@
+"""Deduplicate contact mapping and skip no-op identity updates.
+
+Revision ID: 0010_contact_map_dedup
+Revises: 0009_chat_message_max
+Create Date: 2026-08-05
+"""
+
+from collections.abc import Sequence
+
+from alembic import op
+
+revision: str = "0010_contact_map_dedup"
+down_revision: str | None = "0009_chat_message_max"
+branch_labels: str | Sequence[str] | None = None
+depends_on: str | Sequence[str] | None = None
+
+
+def upgrade() -> None:
+    op.execute(
+        """
+        CREATE OR REPLACE FUNCTION han_app.enqueue_contact_sync()
+        RETURNS trigger
+        LANGUAGE plpgsql
+        SECURITY INVOKER
+        SET search_path = han_app, pg_temp
+        AS $$
+        DECLARE
+            v_entity_id uuid;
+            v_task_type text;
+            v_dedup text;
+        BEGIN
+            IF current_setting('han.sync_suppress', true) = 'true' THEN
+                RETURN NEW;
+            END IF;
+            IF TG_TABLE_NAME = 'user_identities' THEN
+                IF TG_OP = 'UPDATE'
+                   AND NEW.phone_number IS NOT DISTINCT FROM OLD.phone_number
+                   AND NEW.record_status IS NOT DISTINCT FROM OLD.record_status THEN
+                    RETURN NEW;
+                END IF;
+                v_entity_id := NEW.id;
+                v_task_type := CASE WHEN TG_OP = 'INSERT'
+                    THEN 'contact.map_or_create' ELSE 'contact.update' END;
+            ELSE
+                v_entity_id := NEW.user_id;
+                v_task_type := CASE WHEN TG_OP = 'INSERT'
+                    THEN 'contact.map_or_create' ELSE 'contact.update' END;
+            END IF;
+
+            IF v_task_type = 'contact.map_or_create' THEN
+                -- Identity and profile are inserted during the same bootstrap.
+                -- A stable key collapses both triggers into one logical task.
+                v_dedup := v_task_type || ':' || v_entity_id::text;
+            ELSE
+                v_dedup := v_task_type || ':' || v_entity_id::text || ':' ||
+                    encode(public.digest(row_to_json(NEW)::text, 'sha256'), 'hex');
+            END IF;
+
+            INSERT INTO han_app.sync_queue
+                (id, task_type, entity_type, entity_id, dedup_key, payload_json,
+                 status, attempt_count, next_attempt_at, created_at, updated_at)
+            VALUES
+                (gen_random_uuid(), v_task_type, 'contact', v_entity_id, v_dedup,
+                 jsonb_build_object('entity_id', v_entity_id), 'pending', 0,
+                 now(), now(), now())
+            ON CONFLICT (dedup_key) DO NOTHING;
+            RETURN NEW;
+        END;
+        $$
+        """
+    )
+
+
+def downgrade() -> None:
+    raise RuntimeError("Contact map-or-create deduplication migration is forward-only")
diff --git a/codebase/backend/api-backend/app/main.py b/codebase/backend/api-backend/app/main.py
index 5609b1b..aa6ae2d 100644
--- a/codebase/backend/api-backend/app/main.py
+++ b/codebase/backend/api-backend/app/main.py
@@ -175,7 +175,7 @@ async def lifespan(app: FastAPI):
             telemetry.shutdown()
 
 
-EXPECTED_API_DB_REVISION = "0009_chat_message_max"
+EXPECTED_API_DB_REVISION = "0010_contact_map_dedup"
 
 
 app = FastAPI(
diff --git a/codebase/backend/tests/test_config.py b/codebase/backend/tests/test_config.py
index d9f81bb..ff7e64d 100644
--- a/codebase/backend/tests/test_config.py
+++ b/codebase/backend/tests/test_config.py
@@ -270,18 +270,32 @@ class InfrastructureConfigTests(unittest.TestCase):
         sms_db = (ROOT / "sms-service/app/db.py").read_text(encoding="utf-8")
         self.assertNotIn("server_settings", sms_db)
 
-    def test_contact_sync_qualifies_pgcrypto_digest(self) -> None:
+    def test_contact_sync_qualifies_digest_and_deduplicates_initial_map(self) -> None:
         initial = (
             ROOT / "api-backend/alembic/versions/0001_initial_han_app.py"
         ).read_text(encoding="utf-8")
         fix = (
             ROOT / "api-backend/alembic/versions/0002_qualify_pgcrypto_digest.py"
         ).read_text(encoding="utf-8")
+        dedup_fix = (
+            ROOT / "api-backend/alembic/versions/0010_contact_map_dedup.py"
+        ).read_text(encoding="utf-8")
         main = (ROOT / "api-backend/app/main.py").read_text(encoding="utf-8")
         self.assertIn("public.digest(", initial)
         self.assertIn("public.digest(", fix)
         self.assertIn('down_revision: str | None = "0001_initial"', fix)
-        self.assertIn('EXPECTED_API_DB_REVISION = "0009_chat_message_max"', main)
+        self.assertIn("IF v_task_type = 'contact.map_or_create' THEN", dedup_fix)
+        self.assertIn("v_dedup := v_task_type || ':' || v_entity_id::text;", dedup_fix)
+        self.assertIn(
+            "NEW.phone_number IS NOT DISTINCT FROM OLD.phone_number",
+            dedup_fix,
+        )
+        self.assertIn(
+            "NEW.record_status IS NOT DISTINCT FROM OLD.record_status",
+            dedup_fix,
+        )
+        self.assertIn('down_revision: str | None = "0009_chat_message_max"', dedup_fix)
+        self.assertIn('EXPECTED_API_DB_REVISION = "0010_contact_map_dedup"', main)
 
     def test_consent_audit_migration_supports_existing_and_fresh_databases(self) -> None:
         migration = (