Celery

What it does

Celery is a task queue — it lets your Python app kick off time-consuming jobs (sending emails, processing files, running ML models) in the background so the user doesn't have to wait.

When to use it

Use this when your Python app has heavy jobs that shouldn't block the main request — like sending emails, video processing, or running AI models.

Real example

When a user exports a report, it takes 30 seconds to generate. You don't want the user to stare at a loading screen. Prompt: 'Use Celery to create a generate_report task decorated with @shared_task. In the FastAPI route, call generate_report.delay(user_id) and immediately return a job_id. Add a polling endpoint that returns the result when the task is done.'

Good to know

Requires a message broker like Redis or RabbitMQ. More complex to set up than a simple async function.

Alternatives

Install

Use cases

Language

Category

Database & backend