Tutorial - User Guide

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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 fastapi dev with:

fast →fastapi dev main.py
   FastAPI   Starting development server 🚀

             Searching for package file structure from directories
             with __init__.py files
             Importing from /home/user/code/awesomeapp

    module   🐍 main.py

      code   Importing the FastAPI app object from the module with
             the following code:

             from main import app

       app   Using import string: main:app

    server   Server started at http://127.0.0.1:8000
    server   Documentation at http://127.0.0.1:8000/docs

       tip   Running in development mode, for production use:
             fastapi run

             Logs:

      INFO   Will watch for changes in these directories:
             ['/home/user/code/awesomeapp']
      INFO   Uvicorn running on http://127.0.0.1:8000 (Press CTRL+C
             to quit)
      INFO   Started reloader process [383138] using WatchFiles
      INFO   Started server process [383153]
      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.

Make sure you create a virtual environment, activate it, and then install FastAPI:

fast →pip install "fastapi[standard]"

restart ↻

Note

When you install with pip install "fastapi[standard]" it comes with some default optional standard dependencies.

If you don't want to have those optional dependencies, you can instead install pip install fastapi.

Advanced User Guide

There is also an Advanced User Guide that you can read later after this Tutorial - User guide.

The Advanced User Guide builds on this one, uses the same concepts, and teaches you some extra features.

But you should first read the Tutorial - User Guide (what you are reading right now).

It's designed so that you can build a complete application with just the Tutorial - User Guide, and then extend it in different ways, depending on your needs, using some of the additional ideas from the Advanced User Guide.