diff --git a/CHANGELOG.md b/CHANGELOG.md
index 821f32776..08ee3fd52 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,8 @@
 
 ### Features
 
+* add option to Opensearch Output Connector to use parallel bulk implementation (default is True)
+
 ### Improvements
 
 ### Bugfix
diff --git a/logprep/connector/elasticsearch/output.py b/logprep/connector/elasticsearch/output.py
index ccdaa366f..47992c0ca 100644
--- a/logprep/connector/elasticsearch/output.py
+++ b/logprep/connector/elasticsearch/output.py
@@ -311,6 +311,8 @@ def _write_backlog(self):
             max_retries=self._config.max_retries,
             chunk_size=len(self._message_backlog),
         )
+        if self.input_connector and hasattr(self.input_connector, "batch_finished_callback"):
+            self.input_connector.batch_finished_callback()
         self._message_backlog.clear()
 
     def _bulk(self, client, actions, *args, **kwargs):
@@ -324,8 +326,6 @@ def _bulk(self, client, actions, *args, **kwargs):
             self._handle_bulk_index_error(error)
         except search.exceptions.TransportError as error:
             self._handle_transport_error(error)
-        if self.input_connector and hasattr(self.input_connector, "batch_finished_callback"):
-            self.input_connector.batch_finished_callback()
 
     def _handle_serialization_error(self, error: search.SerializationError):
         """Handle serialization error for elasticsearch bulk indexing.
diff --git a/logprep/connector/opensearch/output.py b/logprep/connector/opensearch/output.py
index 5ef371f0c..f0d0bd0a9 100644
--- a/logprep/connector/opensearch/output.py
+++ b/logprep/connector/opensearch/output.py
@@ -72,6 +72,9 @@ class OpensearchOutput(ElasticsearchOutput):
     class Config(ElasticsearchOutput.Config):
         """Config for OpensearchOutput."""
 
+        parallel_bulk: bool = field(default=True, validator=validators.instance_of(bool))
+        """Configure if all events in the backlog should be send, in parallel, via multiple threads
+        to Opensearch. (Default: :code:`True`)"""
         thread_count: int = field(
             default=4, validator=[validators.instance_of(int), validators.gt(1)]
         )
@@ -112,18 +115,10 @@ def describe(self) -> str:
 
     def _bulk(self, client, actions, *args, **kwargs):
         try:
-            for success, item in helpers.parallel_bulk(
-                client,
-                actions=actions,
-                chunk_size=self._config.chunk_size,
-                queue_size=self._config.queue_size,
-                raise_on_error=True,
-                raise_on_exception=True,
-            ):
-                if not success:
-                    result = item[list(item.keys())[0]]
-                    if "error" in result:
-                        raise result.get("error")
+            if self._config.parallel_bulk:
+                self._parallel_bulk(client, actions, *args, **kwargs)
+                return
+            helpers.bulk(client, actions, *args, **kwargs)
         except search.SerializationError as error:
             self._handle_serialization_error(error)
         except search.ConnectionError as error:
@@ -132,5 +127,17 @@ def _bulk(self, client, actions, *args, **kwargs):
             self._handle_bulk_index_error(error)
         except search.exceptions.TransportError as error:
             self._handle_transport_error(error)
-        if self.input_connector:
-            self.input_connector.batch_finished_callback()
+
+    def _parallel_bulk(self, client, actions, *args, **kwargs):
+        for success, item in helpers.parallel_bulk(
+            client,
+            actions=actions,
+            chunk_size=self._config.chunk_size,
+            queue_size=self._config.queue_size,
+            raise_on_error=True,
+            raise_on_exception=True,
+        ):
+            if not success:
+                result = item[list(item.keys())[0]]
+                if "error" in result:
+                    raise result.get("error")
diff --git a/quickstart/exampledata/config/pipeline.yml b/quickstart/exampledata/config/pipeline.yml
index 3890d2bdc..9a47d1a83 100644
--- a/quickstart/exampledata/config/pipeline.yml
+++ b/quickstart/exampledata/config/pipeline.yml
@@ -111,13 +111,11 @@ output:
       - 127.0.0.1:9200
     default_index: processed
     error_index: errors
-    message_backlog_size: 16000
+    message_backlog_size: 10000
     timeout: 10000
     flush_timeout: 60
     max_retries: 3
-    thread_count: 16
-    queue_size: 32
-    chunk_size: 500
+    parallel_bulk: false
     user: admin
     secret: admin
   kafka:
diff --git a/tests/unit/connector/test_opensearch_output.py b/tests/unit/connector/test_opensearch_output.py
index e9c94b907..dce0cb178 100644
--- a/tests/unit/connector/test_opensearch_output.py
+++ b/tests/unit/connector/test_opensearch_output.py
@@ -33,6 +33,7 @@ class NotJsonSerializableMock:
 in_ci = os.environ.get("GITHUB_ACTIONS") == "true"
 
 helpers.parallel_bulk = mock.MagicMock()
+helpers.bulk = mock.MagicMock()
 
 
 class TestOpenSearchOutput(BaseOutputTestCase):
@@ -348,6 +349,7 @@ def test_setup_raises_fatal_output_error_if_opensearch_error_is_raised(self):
             self.object.setup()
 
     def test_setup_registers_flush_timout_tasks(self):
+        # this test fails if opensearch is running on localhost
         job_count = len(Component._scheduler.jobs)
         with pytest.raises(FatalOutputError):
             self.object.setup()