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FastAPI: Fast Production Code

Name: FastAPI: Fast Production Code
Author: fastapi

Get high performance APIs with FastAPI, ideal for startup founders. Build fast with this popular Python framework.

101,589 stars9,782 forksPythonHealth Score 9/10Updated 8/12/2026100% free · open source

What it does

FastAPI helps startup founders build high-performance APIs quickly with a popular Python framework

Install / run

pip install fastapi

When to use it

•You need to create a scalable RESTful API for your startup's web application
•You want to build a real-time API for live updates and streaming data
•You're looking for a framework that supports asynchronous programming and automatic API documentation

Quick start

1Create a new file `main.py` and import FastAPI with `from fastapi import FastAPI`
2Create a FastAPI app instance with `app = FastAPI()`
3Define a route with `@app.get('/')` and a function to handle the request
4Run the app with `uvicorn main:app --reload` to start the development server
5Test the API with a tool like curl or a REST client, e.g. `curl http://localhost:8000/`

Ready-to-paste prompt

Create a simple API to return a JSON response with `@app.get('/items/') def read_items(): return [{'item': 'item1'}, {'item': 'item2'}]`

Heads up: Make sure you have Python 3.7 or later installed, as FastAPI requires it, and also uvicorn for running the app, which can be installed with `pip install uvicorn`

Saves to your device

Topics

api

async

asyncio

fastapi

framework

json

json-schema

openapi

openapi3

pydantic

python

python-types

python3

redoc

rest

starlette

swagger

swagger-ui

uvicorn

web

How FastAPI: Fast Production Code works

Codeflow

Free to inspect

FastAPI: Fast Production Code is a very large Python project (~105k lines across 1145 code files). It is a full software project: use it through its install path rather than reading it end to end. Last commit this month, MIT license, has a test suite.

Size

Very large codebase

~105k lines · 1145 code files · days to read — use, don't read

Setup

Developer setup

A real software project. Use it via its install path; don't expect to read it all.

Runs on

Python

No API keys detected

Python 100%

Where to start reading