User Guide

This tutorial shows you how to use FastAPI with most of its features, step by step.

Each section gradually builds on the previous ones, but it’s structured to separate topics, so that you can go directly to any specific one to solve your specific API needs.

It is also built to work as a future reference.

So you can come back and see exactly what you need.

Run the code

All the code blocks can be copied and used directly (they are actually tested Python files).

To run any of the examples, copy the code to a file main.py, and start uvicorn with:

uvicorn main:app –reload
INFO: Uvicorn running on http://127.0.0.1:8000 (Press CTRL+C to quit)
INFO: Started reloader process [28720]
INFO: Started server process [28722]
INFO: Waiting for application startup.
INFO: Application startup complete.

restart ↻

It is HIGHLY encouraged that you write or copy the code, edit it and run it locally.

Using it in your editor is what really shows you the benefits of FastAPI, seeing how little code you have to write, all the type checks, autocompletion, etc.

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Install FastAPI¶

The first step is to install FastAPI.

For the tutorial, you might want to install it with all the optional dependencies and features:

pip install "fastapi[all]"

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restart ↻

…that also includes uvicorn, that you can use as the server that runs your code.

Note

You can also install it part by part.

This is what you would probably do once you want to deploy your application to production:pip install fastapi

Also install uvicorn to work as the server:pip install "uvicorn[standard]"

And the same for each of the optional dependencies that you want to use.