Why FastAPI?

Introduction to FastAPI

Matt Eckerle

Software and Data Engineering Leader

What is FastAPI?

Let's start with some terminology

API: Application Programming Interface - refers to web applications using the HTTP protocol to transmit structured data
Web Application: application that serves traffic over the web
Web Framework: software framework that helps build web applications

FastAPI is a fast way to build high-performance APIs using Python

FastAPI key features

Fast: Very high performance
"Low code" and easy to learn: Python annotations and type hints
Robust: Production-ready code with autodoc
Standards-based: Based on OpenAPI and JSON Schema

FastAPI logo

OpenAPI logo

JSON logo

¹ https://fastapi.tiangolo.com/

FastAPI vs. other Python web frameworks

Flask

Build web-based (GUI) apps
ORM optional

FastAPI

Build APIs
ORM optional

Django

Build web-based (GUI) apps
ORM built in

Key differences

For APIs without database operations
Data and machine learning transactions

Building our first web application with FastAPI

1. Install FastAPI

pip install fastapi

2. Create your app in `main.py`

from fastapi import FastAPI

app = FastAPI()

@app.get("/")
def read_root():
    return {"message": "Hello World"}

3. Run the server

fastapi dev main.py

REPL showing FastAPI running

Before we practice with FastAPI

Some notes

Can't run the FastAPI server with the "Run this code" button
Define server code in the Python editor as main.py instead
Run it from the terminal using the command fastapi dev main.py
Verify that the logs in the terminal show Application startup complete.
Stop the live server by pressing Control + C in the same terminal
You should install FastAPI in your own Python environment to get used to practicing there as well

Let's practice!