This document describes the current stable version of Celery (5.5). For development docs, go here.

Internals

Release:

5.5

Date:

May 05, 2025

• Contributors Guide to the Code
  • Philosophy
  • Conventions and Idioms Used
  • Applications vs. “single mode”
  • Module Overview
  • Worker overview
• Celery Deprecation Time-line
  • Removals for version 5.0
  • Removals for version 2.0
• Internals: The worker
  • Introduction
  • Data structures
  • Components
• Message Protocol
  • Task messages
  • Event Messages
• “The Big Instance” Refactor
  • Examples
  • Deprecated
  • Aliases (Pending deprecation)
  • Default App Usage
• Internal Module Reference
  • celery.worker.components
  • celery.worker.loops
  • celery.worker.heartbeat
  • celery.worker.control
  • celery.worker.pidbox
  • celery.worker.autoscale
  • celery.concurrency
  • celery.concurrency.solo
  • celery.concurrency.prefork
  • celery.concurrency.eventlet
  • celery.concurrency.gevent
  • celery.concurrency.thread
  • celery.concurrency.base
  • celery.backends
  • celery.backends.base
  • celery.backends.asynchronous
  • celery.backends.azureblockblob
  • celery.backends.rpc
  • celery.backends.database
  • celery.backends.cache
  • celery.backends.consul
  • celery.backends.couchdb
  • celery.backends.mongodb
  • celery.backends.elasticsearch
  • celery.backends.redis
  • celery.backends.cassandra
  • celery.backends.couchbase
  • celery.backends.arangodb
  • celery.backends.dynamodb
  • celery.backends.filesystem
  • celery.backends.cosmosdbsql
  • celery.backends.s3
  • celery.backends.gcs
  • celery.app.trace
  • celery.app.annotations
  • celery.app.routes
  • celery.security.certificate
  • celery.security.key
  • celery.security.serialization
  • celery.security.utils
  • celery.events.snapshot
  • celery.events.cursesmon
  • celery.events.dumper
  • celery.backends.database.models
  • celery.backends.database.session
  • celery.utils
  • celery.utils.abstract
  • celery.utils.collections
  • celery.utils.nodenames
  • celery.utils.deprecated
  • celery.utils.functional
  • celery.utils.graph
  • celery.utils.objects
  • celery.utils.term
  • celery.utils.time
  • celery.utils.iso8601
  • celery.utils.saferepr
  • celery.utils.serialization
  • celery.utils.sysinfo
  • celery.utils.threads
  • celery.utils.timer2
  • celery.utils.imports
  • celery.utils.log
  • celery.utils.text
  • celery.utils.dispatch
  • celery.utils.dispatch.signal
  • celery.platforms
  • celery._state