Glossary · Web & App Development
Celery
Overview
What Celery is
Celery is a mature, open-source distributed task queue for Python. It lets an application run time-consuming or scheduled work in the background, outside the web request, by sending task messages to a broker, where separate worker processes pick them up and execute them. It is commonly paired with Django, Flask, and FastAPI.
How it works
You define tasks in code; calling a task places a message on a broker such as RabbitMQ or Redis. Worker processes consume those messages and run the tasks, optionally storing results in a result backend. Celery scales by adding more workers, and Celery Beat schedules periodic jobs. It also supports retries, routing, and rate limits.
Why it matters for your business
Celery keeps Python applications responsive by moving heavy work, such as email, data processing, report generation, model inference, and scheduled syncs, off the request path. In backend and API development, a full-service team uses Celery to handle asynchronous workloads and recurring jobs so the user-facing app stays fast under load.
Where we use it
Related Zen in Tech services
How our team puts Celery to work in real projects.
FAQ
Celery — common questions
Celery vs Kafka, are they the same thing?
No. Celery is a task queue that runs background jobs, while Kafka is an event-streaming platform that moves and stores streams of events. Celery executes work; Kafka distributes data. They solve different problems and are sometimes used together.
Which broker should I use with Celery?
RabbitMQ is the recommended and most feature-complete broker for Celery. Redis is a popular, simpler alternative that is easy to set up and often sufficient.
Do I need Celery?
If your Python app has slow tasks or scheduled jobs that shouldn't block web requests, like sending emails or processing files, Celery (or a similar task queue) is worth adding.
Need Celery done right?
Book a free consultation and we’ll map the fastest, most cost-effective path for your project.
Knowledge hub
From our knowledge hub
All articles →How to Reduce AI Voice Agent Latency
How to cut AI voice agent latency to sub-second, human-like turn-taking: where lag comes from (STT, LLM, TTS, network) and the fixes that actually work.
Read · 7 min →AI AutomationAutomating Lead Follow-Up and Onboarding for Coaches and Agencies
Follow-up automation for coaches and agencies: respond to leads in minutes, qualify prospects before calls, and automate onboarding so you focus on clients.
Read · 6 min →Web DevelopmentThe Auto Repair & Dealership Website That Books More Jobs
Auto repair and dealership websites that convert: online booking, fast mobile pages, reviews, and service pages that turn visitors into booked jobs.
Read · 4 min →