Version history

To find out how to migrate your application from a previous version of APScheduler, see the migration section.


  • BREAKING Added the cleanup() scheduler method and a configuration option (cleanup_interval). A corresponding abstract method was added to the DataStore class. This method purges expired job results and schedules that have exhausted their triggers and have no more associated jobs running. Previously, schedules were automatically deleted instantly once their triggers could no longer produce any fire times.

  • BREAKING Made publishing JobReleased events the responsibility of the DataStore implementation, rather than the scheduler, for consistency with the acquire_jobs() method

  • BREAKING The started_at field was moved from Job to JobResult

  • BREAKING Removed the from_url() class methods of SQLAlchemyDataStore, MongoDBDataStore and RedisEventBroker in favor of the ability to pass a connection url to the initializer

  • Added the ability to pause and unpause schedules (PR by @WillDaSilva)

  • Added the scheduled_start field to the JobAcquired event

  • Added the scheduled_start and started_at fields to the JobReleased event

  • Fixed large parts of MongoDBDataStore still calling blocking functions in the event loop thread

  • Fixed JSON serialization of triggers that had been used at least once

  • Fixed dialect name checks in the SQLAlchemy job store

  • Fixed JSON and CBOR serializers unable to serialize enums

  • Fixed infinite loop in CalendarIntervalTrigger with UTC timezone (PR by unights)

  • Fixed scheduler not resuming job processing when max_concurrent_jobs had been reached and then a job was completed, thus making job processing possible again (PR by MohammadAmin Vahedinia)

  • Fixed the shutdown procedure of the Redis event broker

  • Fixed SQLAlchemyDataStore not respecting custom schema name when creating enums

  • Fixed skipped intervals with overlapping schedules in AndTrigger (#911 <>_; PR by Bennett Meares)

  • Fixed implicitly created client instances in data stores and event brokers not being closed along with the store/broker


  • BREAKING Renamed any leftover fields named executor to job_executor (this breaks data store compatibility)

  • BREAKING Switched to using the timezone aware timestamp column type on Oracle

  • BREAKING Fixed precision issue with interval columns on MySQL

  • BREAKING Fixed datetime comparison issues on SQLite and MySQL

  • BREAKING Worked around datetime microsecond precision issue on MongoDB

  • BREAKING Renamed the worker_id field to scheduler_id in the JobAcquired and JobReleased events

  • BREAKING Added the task_id attribute to the ScheduleAdded, ScheduleUpdated and ScheduleRemoved events

  • BREAKING Added the finished attribute to the ScheduleRemoved event

  • BREAKING Added the logger parameter to Datastore.start() and EventBroker.start() to make both use the scheduler’s assigned logger

  • BREAKING Made the apscheduler.marshalling module private

  • Added the configure_task() and get_tasks() scheduler methods

  • Fixed out of order delivery of events delivered using worker threads

  • Fixed schedule processing not setting job start deadlines correctly


  • BREAKING The scheduler classes were moved to be importable (only) directly from the apscheduler package (apscheduler.Scheduler and apscheduler.AsyncScheduler)

  • BREAKING Removed the “tags” field in schedules and jobs (this will be added back when the feature has been fully thought through)

  • BREAKING Removed the JobInfo class in favor of just using the Job class (which is now immutable)

  • BREAKING Workers were merged into schedulers. As the Worker and AsyncWorker classes have been removed, you now need to pass role=SchedulerRole.scheduler to the scheduler to prevent it from processing due jobs. The worker event classes (WorkerEvent, WorkerStarted, WorkerStopped) have also been removed.

  • BREAKING The synchronous interfaces for event brokers and data stores have been removed. Synchronous libraries can still be used to implement these services through the use of anyio.to_thread.run_sync().

  • BREAKING The current_worker context variable has been removed

  • BREAKING The current_scheduler context variable is now specified to only contain the currently running instance of a synchronous scheduler (apscheduler.Scheduler). The asynchronous scheduler instance can be fetched from the new current_async_scheduler context variable, and will always be available when a scheduler is running in the current context, while current_scheduler is only available when the synchronous wrapper is being run.

  • BREAKING Changed the initialization of data stores and event brokers to use a single start() method that accepts an AsyncExitStack (and, depending on the interface, other arguments too)

  • BREAKING Added a concept of “job executors”. This determines how the task function is executed once picked up by a worker. Several data structures and scheduler methods have a new field/parameter for this, job_executor. This addition requires database schema changes too.

  • Dropped support for Python 3.7

  • Added support for Python 3.12

  • Added the ability to run jobs in worker processes, courtesy of the processpool executor

  • Added the ability to run jobs in the Qt event loop via the qt executor

  • Added the get_jobs() scheduler method

  • The synchronous scheduler now runs an asyncio event loop in a thread, acting as a façade for AsyncScheduler

  • Fixed the schema parameter in SQLAlchemyDataStore not being applied

  • Fixed SQLalchemy 2.0 compatibility


  • BREAKING Changed the scheduler API to always require a call to either run_until_stopped() or start_in_background() to start the scheduler (using it as a context manager is no longer enough)

  • BREAKING Replaced from_asyncpg_pool() with from_dsn() in the asyncpg event broker

  • Added an async Redis event broker

  • Added automatic reconnection to the Redis event brokers (sync and async)

  • Added automatic reconnection to the asyncpg event broker

  • Changed from_async_sqla_engine() in asyncpg event broker to only copy the connection options instead of directly using the engine

  • Simplified the MQTT event broker by providing a default client instance if omitted

  • Fixed CancelledError being reported as a crash on Python 3.7

  • Fixed JSON/CBOR serialization of JobReleased events


This was a major rewrite/redesign of most parts of the project. See the migration section section for details.


The v4.0 series is provided as a pre-release and may change in a backwards incompatible fashion without any migration pathway, so do NOT use this release in production!

  • Made persistent data stores shareable between multiple processes and nodes

  • Enhanced data stores to be more resilient against temporary connectivity failures

  • Refactored executors (now called workers) to pull jobs from the data store so they can be run independently from schedulers

  • Added full async support (asyncio and Trio) via AnyIO

  • Added type annotations to the code base

  • Added the ability to queue jobs directly without scheduling them

  • Added alternative serializers (CBOR, JSON)

  • Added the CalendarInterval trigger

  • Added the ability to access the current scheduler (under certain circumstances), current worker and the currently running job via context-local variables

  • Added schedule level support for jitter

  • Made triggers stateful

  • Added threshold support for AndTrigger

  • Migrated from pytz time zones to standard library zoneinfo zones

  • Allowed a wider range of tzinfo implementations to be used (though zoneinfo is preferred)

  • Changed IntervalTrigger to start immediately instead of first waiting for one interval

  • Changed CronTrigger to use Sunday as weekday number 0, as per the crontab standard

  • Dropped support for Python 2.X, 3.5 and 3.6

  • Dropped support for the Qt, Twisted, Tornado and Gevent schedulers

  • Dropped support for the Redis, RethinkDB and Zookeeper job stores


  • Removed a leftover check for pytz localize() and normalize() methods


  • Added support for PySide6 to the Qt scheduler

  • No longer enforce pytz time zones (support for others is experimental in the 3.x series)

  • Fixed compatibility with PyMongo 4

  • Fixed pytz deprecation warnings

  • Fixed RuntimeError when shutting down the scheduler from a scheduled job


  • Allowed the use of tzlocal v4.0+ in addition to v2.*


  • Allowed passing through keyword arguments to the underlying stdlib executors in the thread/process pool executors (PR by Albert Xu)


  • Dropped support for Python 3.4

  • Added PySide2 support (PR by Abdulla Ibrahim)

  • Pinned tzlocal to a version compatible with pytz

  • Ensured that jitter is always non-negative to prevent triggers from firing more often than intended

  • Changed AsyncIOScheduler to obtain the event loop in start() instead of __init__(), to prevent situations where the scheduler won’t run because it’s using a different event loop than then one currently running

  • Made it possible to create weak references to Job instances

  • Made the schedulers explicitly raise a descriptive TypeError when serialization is attempted

  • Fixed Zookeeper job store using backslashes instead of forward slashes for paths on Windows (PR by Laurel-rao)

  • Fixed deprecation warnings on the MongoDB job store and increased the minimum PyMongo version to 3.0

  • Fixed BlockingScheduler and BackgroundScheduler shutdown hanging after the user has erroneously tried to start it twice

  • Fixed memory leak when coroutine jobs raise exceptions (due to reference cycles in tracebacks)

  • Fixed inability to schedule wrapped functions with extra arguments when the wrapped function cannot accept them but the wrapper can (original PR by Egor Malykh)

  • Fixed potential where clause error in the SQLAlchemy job store when a subclass uses more than one search condition

  • Fixed a problem where bound methods added as jobs via textual references were called with an unwanted extra self argument (PR by Pengjie Song)

  • Fixed BrokenPoolError in ProcessPoolExecutor so that it will automatically replace the broken pool with a fresh instance


  • Fixed Python 2.7 accidentally depending on the trollius package (regression from v3.6.2)


  • Fixed handling of partial() wrapped coroutine functions in AsyncIOExecutor and TornadoExecutor (PR by shipmints)


  • Fixed OverflowError on Qt scheduler when the wait time is very long

  • Fixed methods inherited from base class could not be executed by processpool executor (PR by Yang Jian)


  • Adapted RedisJobStore to v3.0 of the redis library

  • Adapted RethinkDBJobStore to v2.4 of the rethink library

  • Fixed DeprecationWarnings about on Python 3.7 (PR by Roman Levin)


  • Fixed regression introduced in 3.5.2: Class methods were mistaken for instance methods and thus were broken during serialization

  • Fixed callable name detection for methods in old style classes


  • Fixed scheduling of bound methods on persistent job stores (the workaround of scheduling YourClass.methodname along with an explicit self argument is no longer necessary as this is now done automatically for you)

  • Added the FAQ section to the docs

  • Made BaseScheduler.start() raise a RuntimeError if running under uWSGI with threads disabled


  • Fixed OverflowError on Windows when the wait time is too long

  • Fixed CronTrigger sometimes producing fire times beyond end_date when jitter is enabled (thanks to gilbsgilbs for the tests)

  • Fixed ISO 8601 UTC offset information being silently discarded from string formatted datetimes by adding support for parsing them


  • Added the engine_options option to SQLAlchemyJobStore

  • Added the jitter options to IntervalTrigger and CronTrigger (thanks to gilbsgilbs)

  • Added combining triggers (AndTrigger and OrTrigger)

  • Added better validation for the steps and ranges of different expressions in CronTrigger

  • Added support for named months (jandec) in CronTrigger month expressions

  • Added support for creating a CronTrigger from a crontab expression

  • Allowed spaces around commas in CronTrigger fields

  • Fixed memory leak due to a cyclic reference when jobs raise exceptions (thanks to gilbsgilbs for help on solving this)

  • Fixed passing wait=True to AsyncIOScheduler.shutdown() (although it doesn’t do much)

  • Cancel all pending futures when AsyncIOExecutor is shut down


  • Dropped support for Python 3.3

  • Added the ability to specify the table schema for SQLAlchemyJobStore (thanks to Meir Tseitlin)

  • Added a workaround for the ImportError when used with PyInstaller and the likes (caused by the missing packaging metadata when APScheduler is packaged with these tools)


  • Fixed Python 2.7 compatibility in TornadoExecutor


  • The asyncio and Tornado schedulers can now run jobs targeting coroutine functions (requires Python 3.5; only native coroutines (async def) are supported)

  • The Tornado scheduler now uses TornadoExecutor as its default executor (see above as for why)

  • Added ZooKeeper job store (thanks to Jose Ignacio Villar for the patch)

  • Fixed job store failure (get_due_jobs()) causing the scheduler main loop to exit (it now waits a configurable number of seconds before retrying)

  • Fixed @scheduled_job not working when serialization is required (persistent job stores and ProcessPoolScheduler)

  • Improved import logic in ref_to_obj() to avoid errors in cases where traversing the path with getattr() would not work (thanks to Jarek Glowacki for the patch)

  • Fixed CronTrigger’s weekday position expressions failing on Python 3

  • Fixed CronTrigger’s range expressions sometimes allowing values outside the given range


  • Added the ability to pause and unpause the scheduler

  • Fixed pickling problems with persistent jobs when upgrading from 3.0.x

  • Fixed AttributeError when importing apscheduler with setuptools < 11.0

  • Fixed some events missing from and

  • Fixed wrong run time being set for date trigger when the timezone isn’t the same as the local one

  • Fixed builtin id() erroneously used in MongoDBJobStore’s JobLookupError()

  • Fixed endless loop with CronTrigger that may occur when the computer’s clock resolution is too

    low (thanks to Jinping Bai for the patch)


  • Added RethinkDB job store (contributed by Allen Sanabria)

  • Added method chaining to the modify_job(), reschedule_job(), pause_job() and

    resume_job() methods in BaseScheduler and the corresponding methods in the Job class

  • Added the EVENT_JOB_SUBMITTED event that indicates a job has been submitted to its executor.

  • Added the EVENT_JOB_MAX_INSTANCES event that indicates a job’s execution was skipped due to its maximum number of concurrently running instances being reached

  • Added the time zone to the repr() output of CronTrigger and IntervalTrigger

  • Fixed rare race condition on scheduler shutdown()

  • Dropped official support for CPython 2.6 and 3.2 and PyPy3

  • Moved the connection logic in database backed job stores to the start() method

  • Migrated to setuptools_scm for versioning

  • Deprecated the various version related variables in the apscheduler module (apscheduler.version_info, apscheduler.version, apscheduler.release, apscheduler.__version__)


  • Fixed bug in the cron trigger that produced off-by-1-hour datetimes when crossing the daylight saving threshold (thanks to Tim Strazny for reporting)


  • Fixed cron trigger always coalescing missed run times into a single run time (contributed by Chao Liu)

  • Fixed infinite loop in the cron trigger when an out-of-bounds value was given in an expression

  • Fixed debug logging displaying the next wakeup time in the UTC timezone instead of the scheduler’s configured timezone

  • Allowed unicode function references in Python 2


  • Fixed memory leak in the base executor class (contributed by Stefan Nordhausen)


  • Fixed compatibility with pymongo 3.0


  • Fixed ValueError when the target callable has a default keyword argument that wasn’t overridden

  • Fixed wrong job sort order in some job stores

  • Fixed exception when loading all jobs from the redis job store when there are paused jobs in it

  • Fixed AttributeError when printing a job list when there were pending jobs

  • Added setuptools as an explicit requirement in install requirements


  • A wider variety of target callables can now be scheduled so that the jobs are still serializable (static methods on Python 3.3+, unbound methods on all except Python 3.2)

  • Attempting to serialize a non-serializable Job now raises a helpful exception during serialization. Thanks to Jeremy Morgan for pointing this out.

  • Fixed table creation with SQLAlchemyJobStore on MySQL/InnoDB

  • Fixed start date getting set too far in the future with a timezone different from the local one

  • Fixed _run_job_error() being called with the incorrect number of arguments in most executors


  • Added support for timezones (special thanks to Curtis Vogt for help with this one)

  • Split the old Scheduler class into BlockingScheduler and BackgroundScheduler and added integration for asyncio (PEP 3156), Gevent, Tornado, Twisted and Qt event loops

  • Overhauled the job store system for much better scalability

  • Added the ability to modify, reschedule, pause and resume jobs

  • Dropped the Shelve job store because it could not work with the new job store system

  • Dropped the max_runs option and run counting of jobs since it could not be implemented reliably

  • Adding jobs is now done exclusively through add_job() – the shortcuts to triggers were removed

  • Added the end_date parameter to cron and interval triggers

  • It is now possible to add a job directly to an executor without scheduling, by omitting the trigger argument

  • Replaced the thread pool with a pluggable executor system

  • Added support for running jobs in subprocesses (via the processpool executor)

  • Switched from nose to py.test for running unit tests


  • Added Redis job store

  • Added a “standalone” mode that runs the scheduler in the calling thread

  • Fixed disk synchronization in ShelveJobStore

  • Switched to PyPy 1.9 for PyPy compatibility testing

  • Dropped Python 2.4 support

  • Fixed SQLAlchemy 0.8 compatibility in SQLAlchemyJobStore

  • Various documentation improvements


  • The scheduler now closes the job store that is being removed, and all job stores on shutdown() by default

  • Added the last expression in the day field of CronTrigger (thanks rcaselli)

  • Raise a TypeError when fields with invalid names are passed to CronTrigger (thanks Christy O’Reilly)

  • Fixed the example by shutting down the scheduler on Ctrl+C

  • Added PyPy 1.8 and CPython 3.3 to the test suite

  • Dropped PyPy 1.4 - 1.5 and CPython 3.1 from the test suite

  • Updated setup.cfg for compatibility with distutils2/packaging

  • Examples, documentation sources and unit tests are now packaged in the source distribution


  • Removed the unique constraint from the “name” column in the SQLAlchemy job store

  • Fixed output from Scheduler.print_jobs() which did not previously output a line ending at the end


  • Fixed cron style jobs getting wrong default values


  • Added configurable job stores with several persistent back-ends (shelve, SQLAlchemy and MongoDB)

  • Added the possibility to listen for job events (execution, error, misfire, finish) on a scheduler

  • Added an optional start time for cron-style jobs

  • Added optional job execution coalescing for situations where several executions of the job are due

  • Added an option to limit the maximum number of concurrently executing instances of the job

  • Allowed configuration of misfire grace times on a per-job basis

  • Allowed jobs to be explicitly named

  • All triggers now accept dates in string form (YYYY-mm-dd HH:MM:SS)

  • Jobs are now run in a thread pool; you can either supply your own PEP 3148 compliant thread pool or let APScheduler create its own

  • Maximum run count can be configured for all jobs, not just those using interval-based scheduling

  • Fixed a v1.x design flaw that caused jobs to be executed twice when the scheduler thread was woken up while still within the allowable range of their previous execution time (issues #5, #7)

  • Changed defaults for cron-style jobs to be more intuitive – it will now default to all minimum values for fields lower than the least significant explicitly defined field


  • Fixed time difference calculation to take into account shifts to and from daylight saving time


  • Added __repr__() implementations to expressions, fields, triggers, and jobs to help with debugging

  • Added the dump_jobs method on Scheduler, which gives a helpful listing of all jobs scheduled on it

  • Fixed positional weekday (3th fri etc.) expressions not working except in some edge cases (fixes #2)

  • Removed autogenerated API documentation for modules which are not part of the public API, as it might confuse some users


Positional weekdays are now used with the day field, not weekday.


  • Fixed regression: add_cron_job() in Scheduler was creating a CronTrigger with the wrong parameters (fixes #1, #3)

  • Fixed: if the scheduler is restarted, clear the “stopped” flag to allow jobs to be scheduled again


  • Added the week option for cron schedules

  • Added the daemonic configuration option

  • Fixed a bug in cron expression lists that could cause valid firing times to be missed

  • Fixed unscheduling bound methods via unschedule_func()

  • Changed CronTrigger constructor argument names to match those in Scheduler


  • Fixed a corner case where the combination of hour and day_of_week parameters would cause incorrect timing for a cron trigger