Automatic API documentation (Swagger UI) in FastAPI - Mini Project: Build & Apply

Automatic API documentation (Swagger UI) with FastAPI

📖 Scenario: You are building a simple web API for a bookstore. You want to make it easy for other developers to see and test your API endpoints without writing extra documentation.

🎯 Goal: Create a FastAPI application that automatically generates interactive API documentation using Swagger UI.

📋 What You'll Learn

Create a FastAPI app instance named app

Define a GET endpoint at /books/ that returns a list of book titles

Use FastAPI's automatic documentation features to enable Swagger UI

Run the app so the documentation is accessible at /docs

💡 Why This Matters

🌍 Real World

APIs are used everywhere to let different programs talk to each other. Automatic documentation helps developers understand and test APIs quickly without extra writing.

💼 Career

Knowing how to build APIs with automatic docs is a key skill for backend developers, making your APIs easier to use and maintain.

1

Create the FastAPI app and initial data

Import FastAPI from fastapi and create an app instance called app. Then create a list called books with these exact strings: 'The Hobbit', '1984', 'Pride and Prejudice'.

FastAPI

from fastapi import FastAPI

# Create the FastAPI app instance
# Your code here

# Create the list of books
# Your code here

Need a hint?

Use app = FastAPI() to create the app. Define books as a list with the exact book titles.

2

Add a GET endpoint to return the books list

Use the @app.get decorator with the path /books/ to create a function called read_books that returns the books list.

FastAPI

from fastapi import FastAPI

app = FastAPI()

books = ['The Hobbit', '1984', 'Pride and Prejudice']

# Add GET endpoint for /books/
# Your code here

Need a hint?

Use @app.get('/books/') above the function. The function should return the books list.

3

Verify automatic Swagger UI documentation is enabled

Confirm that the FastAPI app app automatically provides Swagger UI documentation at /docs without extra code. No new code is needed here, just keep the existing code.

FastAPI

from fastapi import FastAPI

app = FastAPI()

books = ['The Hobbit', '1984', 'Pride and Prejudice']

@app.get('/books/')
def read_books():
    return books

# No new code needed here to enable Swagger UI
# Your code here

Need a hint?

FastAPI enables Swagger UI automatically when you create app = FastAPI(). No extra code is needed.

4

Run the FastAPI app with Uvicorn

Add the code to run the app using uvicorn when the script is executed directly. Use if __name__ == '__main__': and call uvicorn.run with app, host '127.0.0.1', and port 8000.

FastAPI

from fastapi import FastAPI
import uvicorn

app = FastAPI()

books = ['The Hobbit', '1984', 'Pride and Prejudice']

@app.get('/books/')
def read_books():
    return books

# Add code to run the app with uvicorn
# Your code here

Need a hint?

Import uvicorn. Use if __name__ == '__main__': to run uvicorn.run(app, host='127.0.0.1', port=8000).