Why structured responses matter in FastAPI - See It in Action

Why structured responses matter

📖 Scenario: You are building a simple web API using FastAPI. Your API will return information about books. To make it easy for users and other developers to understand and use your API, you want to send responses in a clear, consistent structure.

🎯 Goal: Create a FastAPI app that returns book data in a structured JSON format with keys title, author, and year. This helps clients know exactly what to expect in the response.

📋 What You'll Learn

Create a list of dictionaries with book details

Add a configuration variable for minimum publication year

Filter books published after the minimum year using a list comprehension

Return the filtered books as a JSON response using FastAPI

💡 Why This Matters

🌍 Real World

APIs often serve data to websites and apps. Structured responses ensure all clients get data in a predictable format.

💼 Career

Understanding how to build clear, structured API responses is essential for backend developers and full-stack engineers.

1

Create the initial book data

Create a list called books with these exact dictionaries: {'title': '1984', 'author': 'George Orwell', 'year': 1949}, {'title': 'Brave New World', 'author': 'Aldous Huxley', 'year': 1932}, and {'title': 'Fahrenheit 451', 'author': 'Ray Bradbury', 'year': 1953}.

FastAPI

# Your code here

Need a hint?

Use a list with dictionaries inside. Each dictionary has keys title, author, and year.

2

Add a minimum year filter

Create a variable called min_year and set it to 1940. This will be used to filter books published after this year.

FastAPI

books = [
    {'title': '1984', 'author': 'George Orwell', 'year': 1949},
    {'title': 'Brave New World', 'author': 'Aldous Huxley', 'year': 1932},
    {'title': 'Fahrenheit 451', 'author': 'Ray Bradbury', 'year': 1953}
]
# Your code here

Need a hint?

Just create a variable named min_year and assign the number 1940.

3

Filter books published after the minimum year

Create a new list called filtered_books using a list comprehension that includes only books from books where the year is greater than min_year.

FastAPI

books = [
    {'title': '1984', 'author': 'George Orwell', 'year': 1949},
    {'title': 'Brave New World', 'author': 'Aldous Huxley', 'year': 1932},
    {'title': 'Fahrenheit 451', 'author': 'Ray Bradbury', 'year': 1953}
]

min_year = 1940
# Your code here

Need a hint?

Use a list comprehension with for book in books and an if condition checking book['year'] > min_year.

4

Return the filtered books as a JSON response

Import FastAPI from fastapi and JSONResponse from fastapi.responses. Create an app instance called app. Define a GET route at /books that returns filtered_books wrapped in JSONResponse.

FastAPI

books = [
    {'title': '1984', 'author': 'George Orwell', 'year': 1949},
    {'title': 'Brave New World', 'author': 'Aldous Huxley', 'year': 1932},
    {'title': 'Fahrenheit 451', 'author': 'Ray Bradbury', 'year': 1953}
]

min_year = 1940

filtered_books = [book for book in books if book['year'] > min_year]

# Your code here

Need a hint?

Import FastAPI and JSONResponse. Create app = FastAPI(). Use @app.get('/books') decorator. Define async function get_books() that returns JSONResponse(content=filtered_books).