Implement Background Tasks in FastAPI

What are background tasks?

Often when you get a request from a client, you do not want your API to process that data completely, else you will have to send a confirmation as soon as you receive a request and process that data or operation in the background. In other words, these are useful for operations that need to happen after a request, but the client doesn’t need to wait for the operation to get completed before receiving the response. For example:

• Email notifications sent after performing some action: Connecting to an email server and then sending an email could be a slow (several seconds) process. We can return the response right away and send the email notification in the background.

• Processing data: Let’s say you receive a file that must go through a file-processing operation. you can return the Accepted (HTTP 202) response and process the operation in the background.

You can easily implement this background processing in FastAPI. Let us see how we can achieve this.

Implementing background tasks in FastAPI

You can define background tasks to be run after returning a response(kind-of confirmation).

Let us see the code now.