Email new signups without blocking your response

The signup endpoint takes three seconds because it waits for the welcome email to send before it replies.

Intermediate to advancedRead 5 minDoing: an hour, with your project open7 steps

What you'll have at the end

A signup endpoint that answers in about a hundredth of a second while the welcome email sends on its own, a couple of seconds later.

Before you start

You need

A signup route that already creates the new user and calls a working, synchronous email-sending function directly, so the client's response only comes back once that call finishes.

Not covered

Choosing a durable task queue for work that has to survive a crash; this only moves a fire-and-forget email off the response, and leaves that choice for later.

Leans on

7 steps

Where to go next

Move a slow task off the request and into a background queue

reach for this instead when losing the task on a crash actually matters, a payment receipt or anything the business can't silently drop, since a background task disappears with the worker process.

Checked 18 Aug 2026

Part of the FastAPI cookbook