diff --git a/configs/development.ini b/configs/development.ini
index a832a132..f9bb25cb 100644
--- a/configs/development.ini
+++ b/configs/development.ini
@@ -419,6 +419,15 @@ archive_cache.filesystem.retry_attempts = 10
 
 use_celery = true
 
+; Enable message deduplication — When enabled, at most one message with the same task name + payload may be present in the queue at a time. (Default: false)
+celery.enable_deduplication = false
+
+; Redis lock store (for deduplication) — Redis connection used to hold deduplication locks. Must be different from celery.broker_url. (Default: redis/9)
+celery.deduplicate_lock_store = redis://redis:6379/9
+
+;Lock TTL (seconds) — Time-to-live for a deduplication lock. After expiry, another message with the same name + payload may be enqueued. (Default: 3600 seconds or 1 hour).
+celery.lock_ttl_seconds = 3600
+
 ; path to store schedule database
 #celerybeat-schedule.path =
 
diff --git a/configs/production.ini b/configs/production.ini
index 7fd8afec..5beb696c 100644
--- a/configs/production.ini
+++ b/configs/production.ini
@@ -381,6 +381,15 @@ archive_cache.filesystem.retry_attempts = 10
 
 use_celery = true
 
+; Enable message deduplication — When enabled, at most one message with the same task name + payload may be present in the queue at a time. (Default: false)
+celery.enable_deduplication = false
+
+; Redis lock store (for deduplication) — Redis connection used to hold deduplication locks. Must be different from celery.broker_url. (Default: redis/9)
+celery.deduplicate_lock_store = redis://redis:6379/9
+
+;Lock TTL (seconds) — Time-to-live for a deduplication lock. After expiry, another message with the same name + payload may be enqueued. (Default: 3600 seconds or 1 hour).
+celery.lock_ttl_seconds = 3600
+
 ; path to store schedule database
 #celerybeat-schedule.path =
 
diff --git a/rhodecode/config/config_maker.py b/rhodecode/config/config_maker.py
index a98a6638..5f710d83 100644
--- a/rhodecode/config/config_maker.py
+++ b/rhodecode/config/config_maker.py
@@ -170,6 +170,9 @@ def sanitize_settings_and_apply_defaults(global_config, settings):
     # celery
     broker_url = settings_maker.make_setting("celery.broker_url", "redis://redis:6379/8", default_when_empty=True)
     settings_maker.make_setting("celery.result_backend", broker_url)
+    settings_maker.make_setting("celery.enable_deduplication", False, parser="bool")
+    settings_maker.make_setting("celery.deduplicate_lock_store", "redis://redis:6379/9", parser="string")
+    settings_maker.make_setting("celery.lock_ttl_seconds", 3600, parser="int")
 
     settings_maker.make_setting("exception_tracker.send_email", False, parser="bool")
     settings_maker.make_setting("exception_tracker.email_prefix", "[RHODECODE ERROR]", default_when_empty=True)
diff --git a/rhodecode/config/middleware.py b/rhodecode/config/middleware.py
index 45700022..9f9978ea 100644
--- a/rhodecode/config/middleware.py
+++ b/rhodecode/config/middleware.py
@@ -147,6 +147,9 @@ def get_celery_config(settings):
             return key_name[len(pref) :].replace(".", "_").lower()
 
     def type_converter(parsed_key, value):
+        if not isinstance(value, str):
+            return value
+
         # cast to int
         if value.isdigit():
             return int(value)
diff --git a/rhodecode/integrations/types/slack.py b/rhodecode/integrations/types/slack.py
index 07898b1e..8e707957 100644
--- a/rhodecode/integrations/types/slack.py
+++ b/rhodecode/integrations/types/slack.py
@@ -25,6 +25,7 @@ import deform.widget
 import colander
 
 from rhodecode import events
+from rhodecode.lib.celerylib.uniqueue_tasks import RequestContextAndUniqueByPayloadTask
 from rhodecode.model.validation_schema.widgets import CheckboxChoiceWidgetDesc
 from rhodecode.translation import _
 from rhodecode.lib import helpers as h
@@ -140,7 +141,7 @@ class SlackIntegrationType(IntegrationTypeBase):
         run_task(post_text_to_slack, self.settings, slack_data)
 
 
-@async_task(ignore_result=True, base=RequestContextTask)
+@async_task(ignore_result=True, base=RequestContextAndUniqueByPayloadTask)
 def post_text_to_slack(settings, slack_data: SlackData):
     # because JSON serialization, if we run async with celery, deserialize to SlackData
     if isinstance(slack_data, dict):
diff --git a/rhodecode/integrations/types/webhook.py b/rhodecode/integrations/types/webhook.py
index 95b0829d..820b0ad0 100644
--- a/rhodecode/integrations/types/webhook.py
+++ b/rhodecode/integrations/types/webhook.py
@@ -24,6 +24,7 @@ import colander
 
 import rhodecode
 from rhodecode import events
+from rhodecode.lib.celerylib.uniqueue_tasks import RequestContextAndUniqueByPayloadTask
 from rhodecode.lib.colander_utils import strip_whitespace
 from rhodecode.model.validation_schema.widgets import CheckboxChoiceWidgetDesc
 from rhodecode.translation import _
@@ -36,7 +37,7 @@ from rhodecode.integrations.types.base import (
     requests_retry_call,
 )
 from rhodecode.integrations.types.handlers.webhook import WebhookDataHandler
-from rhodecode.lib.celerylib import run_task, async_task, RequestContextTask
+from rhodecode.lib.celerylib import run_task, async_task
 from rhodecode.model.validation_schema import widgets
 
 log = logging.getLogger(__name__)
@@ -191,7 +192,7 @@ class WebhookIntegrationType(IntegrationTypeBase):
         run_task(post_to_webhook, self.settings, url_calls)
 
 
-@async_task(ignore_result=True, base=RequestContextTask)
+@async_task(ignore_result=True, base=RequestContextAndUniqueByPayloadTask)
 def post_to_webhook(settings, url_calls):
     """
     Example data::
diff --git a/rhodecode/lib/celerylib/tasks.py b/rhodecode/lib/celerylib/tasks.py
index 52baefc2..2d1e1f6f 100644
--- a/rhodecode/lib/celerylib/tasks.py
+++ b/rhodecode/lib/celerylib/tasks.py
@@ -37,8 +37,9 @@ import rhodecode
 from rhodecode.apps.ai_agents.ai_service import get_ai_service
 from rhodecode.apps.ai_agents.models.base import Response, AIServiceError
 from rhodecode.lib import audit_logger, diffs, codeblocks
-from rhodecode.lib.celerylib import get_logger, async_task, RequestContextTask, run_task
+from rhodecode.lib.celerylib import get_logger, async_task, run_task
 from rhodecode.lib import hooks_base
+from rhodecode.lib.celerylib.uniqueue_tasks import UniqueByPayloadTask, RequestContextAndUniqueByPayloadTask
 from rhodecode.lib.diffs import MAX_CONTEXT
 from rhodecode.lib.str_utils import safe_str
 from rhodecode.lib.utils import adopt_for_celery
@@ -61,7 +62,7 @@ from rhodecode.model.pull_request import PullRequestModel
 from rhodecode.model.settings import SettingsModel
 
 
-@async_task(ignore_result=True, base=RequestContextTask)
+@async_task(ignore_result=True, base=RequestContextAndUniqueByPayloadTask)
 def send_email(recipients, subject, body="", html_body="", email_config=None, extra_headers=None):
     """
     Sends an email with defined parameters from the .ini files.
@@ -142,6 +143,7 @@ def send_email(recipients, subject, body="", html_body="", email_config=None, ex
     return True
 
 
+@async_task(ignore_result=True, base=RequestContextAndUniqueByPayloadTask)
 def transform_legacy_email_config(email_config: dict[Any, Any] | Any, mail_server: Any | None) -> dict[
     str, None | int | bool | str | Any]:
     return dict(
@@ -177,7 +179,7 @@ def get_mailer(transformed_email_conf: dict[str, Any], original_email_conf: dict
     return Mailer(**transformed_email_conf)
 
 
-@async_task(ignore_result=True, base=RequestContextTask)
+@async_task(ignore_result=True, base=RequestContextAndUniqueByPayloadTask)
 def create_repo(form_data, cur_user):
     from rhodecode.model.repo import RepoModel
     from rhodecode.model.user import UserModel
@@ -286,7 +288,7 @@ def create_repo(form_data, cur_user):
     return True
 
 
-@async_task(ignore_result=True, base=RequestContextTask)
+@async_task(ignore_result=True, base=RequestContextAndUniqueByPayloadTask)
 def create_repo_fork(form_data, cur_user):
     """
     Creates a fork of repository using internal VCS methods
@@ -375,7 +377,7 @@ def create_repo_fork(form_data, cur_user):
     return True
 
 
-@async_task(ignore_result=True, base=RequestContextTask)
+@async_task(ignore_result=True, base=RequestContextAndUniqueByPayloadTask)
 def repo_maintenance(repoid):
     from rhodecode.lib import repo_maintenance as repo_maintenance_lib
 
@@ -391,7 +393,7 @@ def repo_maintenance(repoid):
         log.debug("Repo `%s` not found or without a clone_url", repoid)
 
 
-@async_task(ignore_result=True, base=RequestContextTask)
+@async_task(ignore_result=True, base=RequestContextAndUniqueByPayloadTask)
 def check_for_update(send_email_notification=True, email_recipients=None):
     from rhodecode.model.update import UpdateModel
     from rhodecode.model.notification import EmailNotificationModel
@@ -450,24 +452,24 @@ def sync_last_update_for_objects(*args, **kwargs):
                 repo_gr.update_commit_cache()
 
 
-@async_task(ignore_result=True, base=RequestContextTask)
+@async_task(ignore_result=True, base=RequestContextAndUniqueByPayloadTask)
 def test_celery_exception(msg):
     raise Exception(f"Test exception: {msg}")
 
 
-@async_task(ignore_result=True, base=RequestContextTask)
+@async_task(ignore_result=True, base=RequestContextAndUniqueByPayloadTask)
 def sync_last_update(*args, **kwargs):
     sync_last_update_for_objects(*args, **kwargs)
 
 
-@async_task(ignore_result=False)
+@async_task(ignore_result=False, base=UniqueByPayloadTask)
 def beat_check(*args, **kwargs):
     log = get_logger(beat_check)
     log.info("%r: Got args: %r and kwargs %r", beat_check, args, kwargs)
     return time.time()
 
 
-@async_task(ignore_result=True)
+@async_task(ignore_result=True, base=UniqueByPayloadTask)
 def schedule_sync_ldap_ad_users_producer():
     log = get_logger(schedule_sync_ldap_ad_users_producer)
 
@@ -492,7 +494,7 @@ def schedule_sync_ldap_ad_users_producer():
         scheduler.update_from_dict(entries)
 
 
-@async_task(ignore_result=True)
+@async_task(ignore_result=True, base=UniqueByPayloadTask)
 def unschedule_sync_ldap_ad_users_producer():
     log = get_logger(unschedule_sync_ldap_ad_users_producer)
 
@@ -508,7 +510,7 @@ def unschedule_sync_ldap_ad_users_producer():
         Session().delete(existing_task)
 
 
-@async_task
+@async_task(base=UniqueByPayloadTask)
 def start_ai_code_review(pull_request_id):
     log = get_logger(start_ai_code_review)
     log.info("Starting AI code review for pull request id: %s", pull_request_id)
@@ -769,7 +771,7 @@ def _get_diffset(
     return diffset.render_patchset(_parsed, source_ref=source_ref_id, target_ref=target_ref_id)
 
 
-@async_task
+@async_task(base=UniqueByPayloadTask)
 @adopt_for_celery
 def repo_size(extras):
     from rhodecode.lib.hooks_base import repo_size
@@ -777,7 +779,7 @@ def repo_size(extras):
     return repo_size(extras)
 
 
-@async_task
+@async_task(base=UniqueByPayloadTask)
 @adopt_for_celery
 def pre_pull(extras):
     from rhodecode.lib.hooks_base import pre_pull
@@ -785,7 +787,7 @@ def pre_pull(extras):
     return pre_pull(extras)
 
 
-@async_task
+@async_task(base=UniqueByPayloadTask)
 @adopt_for_celery
 def post_pull(extras):
     from rhodecode.lib.hooks_base import post_pull
@@ -793,7 +795,7 @@ def post_pull(extras):
     return post_pull(extras)
 
 
-@async_task
+@async_task(base=UniqueByPayloadTask)
 @adopt_for_celery
 def pre_push(extras):
     from rhodecode.lib.hooks_base import pre_push
@@ -801,7 +803,7 @@ def pre_push(extras):
     return pre_push(extras)
 
 
-@async_task
+@async_task(base=UniqueByPayloadTask)
 @adopt_for_celery
 def post_push(extras):
     from rhodecode.lib.hooks_base import post_push
diff --git a/rhodecode/lib/celerylib/tests/__init__.py b/rhodecode/lib/celerylib/tests/__init__.py
new file mode 100644
index 00000000..e69de29b
diff --git a/rhodecode/lib/celerylib/tests/test_uniqueue_task.py b/rhodecode/lib/celerylib/tests/test_uniqueue_task.py
new file mode 100644
index 00000000..17129f00
--- /dev/null
+++ b/rhodecode/lib/celerylib/tests/test_uniqueue_task.py
@@ -0,0 +1,14 @@
+from rhodecode.lib.celerylib.uniqueue_tasks import stable_payload_key
+
+
+class TestUniqueTask:
+    def test_stable_payload_key_generation(self):
+        task_name = "test_task"
+        task_args = (1, 2, 3)
+        task_kwargs = {"arg1": 10}
+
+        expected_output = "celery:unique:test_task:463d9df63be487de5fd2073cfc26a6813713ee96c0cf9f7b5f949e12b8643511"
+
+        for _ in range(10):
+            res = stable_payload_key(task_name, task_args, task_kwargs)
+            assert res == expected_output
diff --git a/rhodecode/lib/celerylib/uniqueue_tasks.py b/rhodecode/lib/celerylib/uniqueue_tasks.py
new file mode 100644
index 00000000..ba1452af
--- /dev/null
+++ b/rhodecode/lib/celerylib/uniqueue_tasks.py
@@ -0,0 +1,139 @@
+import logging
+import json
+import uuid
+import hashlib
+import redis
+from celery import Task
+
+from rhodecode import CONFIG
+from rhodecode.lib.celerylib import RequestContextTask
+
+log = logging.getLogger(__name__)
+
+
+def stable_payload_key(task_name: str, args: tuple, kwargs: dict) -> str:
+    """Deterministic key from (name, args, kwargs) ignoring any private kwargs."""
+    clean_kwargs = {k: v for k, v in kwargs.items() if not k.startswith("_")}
+    payload = json.dumps([task_name, args, clean_kwargs], sort_keys=True, separators=(",", ":"))
+    digest = hashlib.sha256(payload.encode()).hexdigest()
+    return f"celery:unique:{task_name}:{digest}"
+
+
+class UniqueByPayloadTask(Task):
+    """Base task that deduplicates by (task name + args + kwargs) at enqueue time."""
+
+    abstract = True
+
+    _redis_url = None
+    _lock_ttl_seconds = None
+    _redis_connection = None
+    _deduplication_enabled = None
+    _redis_available = None
+
+    @classmethod
+    def redis_url(cls):
+        if cls._redis_url is None:
+            cls._redis_url = CONFIG["celery.deduplicate_lock_store"]
+        return cls._redis_url
+
+    @classmethod
+    def _redis(cls):
+        if cls._redis_connection is None:
+            log.debug("Connecting to Redis at %s", cls.redis_url())
+            cls._redis_connection = redis.from_url(cls.redis_url())
+        return cls._redis_connection
+
+    @property
+    def deduplication_enabled(self):
+        if self._deduplication_enabled is None:
+            self._deduplication_enabled = CONFIG["celery.enable_deduplication"]
+        return self._deduplication_enabled
+
+    @property
+    def lock_ttl_seconds(self):
+        if self._lock_ttl_seconds is None:
+            self._lock_ttl_seconds = CONFIG["celery.lock_ttl_seconds"]
+        return self._lock_ttl_seconds
+
+    def _unique_key(self, args, kwargs) -> str:
+        return stable_payload_key(self.name, args, kwargs)
+
+    def apply_async(
+        self, args=None, kwargs=None, task_id=None, producer=None, link=None, link_error=None, shadow=None, **options
+    ):
+        """
+        If another identical (name+payload) task is queued/running,
+        return its AsyncResult instead of enqueueing a new message.
+        """
+
+        self._validate_config_and_redis_available()
+
+        if not self.deduplication_enabled:
+            log.debug("Deduplication disabled; skipping unique key check")
+            return super().apply_async(args, kwargs, task_id, producer, link, link_error, shadow, **options)
+
+        args = args or ()
+        kwargs = kwargs or {}
+
+        key = self._unique_key(args, kwargs)
+        r = self._redis()
+
+        # Generate a task_id up front so we can store/return it consistently.
+        task_id = uuid.uuid4().hex
+
+        # Atomically claim the key if absent
+        claimed = r.set(key, task_id, nx=True, ex=self.lock_ttl_seconds)
+        log.debug("Task %s unique key claim: %s", key, claimed)
+        if not claimed:
+            # Someone else already queued (or is running) the same task.
+            from celery.result import AsyncResult
+
+            existing = r.get(key)
+            log.debug("Task %s already queued or running; returning existing result", key)
+            return AsyncResult((existing or b"").decode() or None, app=self._get_app())
+
+        options["headers"] = options.get("headers", {})
+        options["headers"].update({"unique_key": key})
+
+        return super().apply_async(args, kwargs, task_id, producer, link, link_error, shadow, **options)
+
+    def after_return(self, status, retval, task_id, args, kwargs, einfo):
+        if not self.deduplication_enabled:
+            log.debug("Deduplication disabled; skipping unique key check")
+            return super().after_return(status, retval, task_id, args, kwargs, einfo)
+
+        key = None
+        try:
+            key = getattr(self.request, "headers", {}).get("unique_key")
+            log.debug("Deleting lock %s", key)
+            if key:
+                self._redis().delete(key)
+        except Exception as e:
+            # Don't crash the worker if Redis is momentarily unavailable.
+            if key:
+                log.warning("Failed to delete lock %s: %s", key, e)
+
+        return super().after_return(status, retval, task_id, args, kwargs, einfo)
+
+    def _validate_config_and_redis_available(self):
+        if (
+            CONFIG.get("celery.enable_deduplication") is None
+            or CONFIG.get("celery.deduplicate_lock_store") is None
+            or CONFIG.get("celery.lock_ttl_seconds") is None
+        ):
+            log.warning("Missing config; unique task deduplication disabled")
+            self._deduplication_enabled = False
+            self._redis_available = False
+
+        if self._redis_available is None:
+            try:
+                self._redis()
+                self._redis_available = True
+            except Exception as e:
+                log.warning("Failed to connect to Redis: %s; unique task deduplication disabled", e)
+                self._deduplication_enabled = False
+                self._redis_available = False
+
+
+class RequestContextAndUniqueByPayloadTask(RequestContextTask, UniqueByPayloadTask):
+    abstract = True