diff --git a/resources/config.sample.json b/resources/config.sample.json
index 3d6c956..1615a09 100644
--- a/resources/config.sample.json
+++ b/resources/config.sample.json
@@ -1,4 +1,6 @@
 {
+  "nexus_file": "",
+  "done_writing_message_file": "",
   "config_file": "",
   "id": "",
   "dataset": {
@@ -17,6 +19,8 @@
     "offline_ingestor_executable": [
       "background_ingestor"
     ],
+    "max_offline_ingestors": 10,
+    "offline_ingestors_wait_time": 10,
     "schemas_directory": "schemas",
     "check_if_dataset_exists_by_pid": true,
     "check_if_dataset_exists_by_metadata": true,
diff --git a/src/scicat_configuration.py b/src/scicat_configuration.py
index 687fe78..7d9ee18 100644
--- a/src/scicat_configuration.py
+++ b/src/scicat_configuration.py
@@ -232,6 +232,8 @@ class IngestionOptions:
     offline_ingestor_executable: list[str] = field(
         default_factory=default_offline_ingestor_executable
     )
+    max_offline_ingestors: int = 10
+    offline_ingestors_wait_time: int = 10
     schemas_directory: str = "schemas"
     check_if_dataset_exists_by_pid: bool = True
     check_if_dataset_exists_by_metadata: bool = True
@@ -309,6 +311,8 @@ class OnlineIngestorConfig:
     # original_dict: Mapping
     """Original configuration dictionary in the json file."""
 
+    nexus_file: str = ""
+    done_writing_message_file: str = ""
     config_file: str
     id: str = ""
     dataset: DatasetOptions = field(default_factory=DatasetOptions)
diff --git a/src/scicat_online_ingestor.py b/src/scicat_online_ingestor.py
index fa00314..0ac6723 100644
--- a/src/scicat_online_ingestor.py
+++ b/src/scicat_online_ingestor.py
@@ -6,6 +6,7 @@
 import logging
 import pathlib
 import subprocess
+from time import sleep
 
 try:
     __version__ = importlib.metadata.version(__package__ or __name__)
@@ -59,7 +60,14 @@ def dump_message_to_file_if_needed(
     logger.info("Message file saved")
 
 
-def _individual_message_commit(offline_ingestors, consumer, logger: logging.Logger):
+def _individual_message_commit(job_id, message, consumer, logger: logging.Logger):
+    logger.info("Executing commit for message with job id %s", job_id)
+    consumer.commit(message=message)
+
+
+def _check_offline_ingestors(
+    offline_ingestors, consumer, config, logger: logging.Logger
+) -> int:
     logger.info("%s offline ingestors running", len(offline_ingestors))
     for job_id, job_item in offline_ingestors.items():
         result = job_item["proc"].poll()
@@ -69,8 +77,12 @@ def _individual_message_commit(offline_ingestors, consumer, logger: logging.Logg
             )
             if result == 0:
                 logger.info("Offline ingestor successful for job id %s", job_id)
-                logger.info("Executing commit for message with job id %s", job_id)
-                consumer.commit(message=job_item["message"])
+                # if background process is successful
+                # check if we need to commit the individual message
+                if config.kafka.individual_message_commit:
+                    _individual_message_commit(
+                        job_id, job_item["message"], consumer, logger
+                    )
             else:
                 logger.error("Offline ingestor error for job id %s", job_id)
             logger.info(
@@ -78,6 +90,8 @@ def _individual_message_commit(offline_ingestors, consumer, logger: logging.Logg
             )
             offline_ingestors.pop(job_id)
 
+    return len(offline_ingestors)
+
 
 def build_online_config(logger: logging.Logger | None = None) -> OnlineIngestorConfig:
     arg_parser = build_arg_parser(
@@ -166,16 +180,28 @@ def main() -> None:
                 if config.ingestion.dry_run:
                     logger.info("Dry run mode enabled. Skipping background ingestor.")
                 else:
+                    logger.info("Checking number of offline ingestor")
+                    offline_ingestor_runnings: int = _check_offline_ingestors(
+                        offline_ingestors, consumer, config, logger
+                    )
+                    while (
+                        offline_ingestor_runnings
+                        >= config.ingestion.max_offline_ingestors
+                    ):
+                        sleep(config.ingestion.offline_ingestors_wait_time)
+                        offline_ingestor_runnings = _check_offline_ingestors(
+                            offline_ingestors, consumer, config, logger
+                        )
+
+                    logger.info(
+                        "Offline ingestors currently running %s",
+                        offline_ingestor_runnings,
+                    )
                     logger.info("Running background ingestor with command above")
                     proc = subprocess.Popen(cmd)  #  noqa: S603
                     # save info about the background process
                     offline_ingestors[job_id] = {"proc": proc, "message": message}
 
-                    # if background process is successful
-                    # check if we need to commit the individual message
-                    if config.kafka.individual_message_commit:
-                        _individual_message_commit(offline_ingestors, consumer, logger)
-
 
 if __name__ == "__main__":
     main()