FastAPI Getting Started Tutorial: Building Your First API with Python 3.11

FastAPI is a modern, fast (high-performance), web framework for building APIs with Python 3.11. It is easy to learn and use, making it an excellent choice for developers who want to create APIs quickly and efficiently. In this tutorial, we will walk through the steps to build your first API using FastAPI.

Prerequisites

Python 3.11 installed on your system
Basic knowledge of Python programming
Text editor or IDE (such as VS Code)
Internet connection to install packages

Installing FastAPI and Uvicorn

First, open your terminal or command prompt and install FastAPI along with Uvicorn, an ASGI server that runs your application:

pip install fastapi uvicorn

Creating Your First API

Create a new Python file named main.py in your project directory. This file will contain your API code.

from fastapi import FastAPI

app = FastAPI()

@app.get("/")
async def read_root():
    return {"message": "Hello, FastAPI with Python 3.11!"}

Running the API Server

Use Uvicorn to run your FastAPI application. In your terminal, execute:

uvicorn main:app --reload

The –reload flag enables auto-reloading of the server when you make code changes, ideal for development.

Accessing Your API

Open your web browser and navigate to http://127.0.0.1:8000/. You should see a JSON response:

{"message": "Hello, FastAPI with Python 3.11!"}

Exploring Automatic Documentation

FastAPI automatically generates interactive API documentation. Visit:

Next Steps

Now that you have a basic API running, you can extend it by adding more endpoints, handling data input, connecting to databases, and deploying your application. FastAPI’s documentation provides comprehensive guides for advanced features.

Happy coding with FastAPI and Python 3.11!

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