What is a FastAPI Background Task?

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One of the powerful features of FastAPI is its ability to handle background tasks efficiently. This article will delve into background tasks in FastAPI, compare them with Celery, and provide examples, including adding middleware as a background task.

What are Background Tasks?

Background tasks run asynchronously and do not block the main application flow. These tasks are useful for operations that take time but can be completed after a while, such as sending emails, processing large files, or making API calls to third-party services.

Let’s understand the concept of using background tasks in FastAPI with a real example: sending a welcome email when a user registers to our application.

from fastapi import FastAPI, BackgroundTasks

app = FastAPI()

def send_welcome_message(message: str):
    """
      sending to particular user
    """
    pass


@app.post("/send-email/")
async def UserRegistration(background_tasks: BackgroundTasks, email: str):
    """
      write here you user registration logic
    """
    if user_created_successfully:
        background_tasks.add_task(send_welcome_message, f"Email sent to: {email}")
    return {"message": "User Registration is…