Why APIs matter in Flask - See It in Action

Why APIs Matter with Flask

📖 Scenario: You are building a simple web service that shares information about books. This service will let other programs ask for book details easily.

🎯 Goal: Create a basic Flask API that returns book information as JSON data when requested.

📋 What You'll Learn

Create a dictionary called books with three books and their authors

Create a variable called api_prefix set to "/api"

Create a Flask route at "/api/books" that returns the books dictionary as JSON

Run the Flask app with debug mode enabled

💡 Why This Matters

🌍 Real World

APIs let different programs talk to each other easily. For example, a mobile app can ask your Flask API for book info to show to users.

💼 Career

Understanding how to build and run APIs with Flask is a key skill for backend web developers and software engineers.

1

Create the book data dictionary

Create a dictionary called books with these exact entries: "1984": "George Orwell", "To Kill a Mockingbird": "Harper Lee", and "The Great Gatsby": "F. Scott Fitzgerald".

Flask

# Create the books dictionary with exact entries
# Your code here

Need a hint?

Use curly braces {} to create a dictionary with keys as book titles and values as authors.

2

Add the API prefix variable

Create a variable called api_prefix and set it to the string "/api".

Flask

books = {
    "1984": "George Orwell",
    "To Kill a Mockingbird": "Harper Lee",
    "The Great Gatsby": "F. Scott Fitzgerald"
}
# Create the api_prefix variable
# Your code here

Need a hint?

Just assign the string "/api" to the variable api_prefix.

3

Create the Flask route to return books

Import Flask and jsonify from flask. Create a Flask app called app. Then create a route using @app.route(f"{api_prefix}/books") that returns the books dictionary as JSON using jsonify(books).

Flask

books = {
    "1984": "George Orwell",
    "To Kill a Mockingbird": "Harper Lee",
    "The Great Gatsby": "F. Scott Fitzgerald"
}

api_prefix = "/api"

# Import Flask and jsonify, create app, and add route to return books as JSON
# Your code here

Need a hint?

Use @app.route with the path built from api_prefix. Return the dictionary wrapped in jsonify().

4

Run the Flask app with debug mode

Add the code to run the Flask app with debug=True inside the if __name__ == '__main__': block.

Flask

from flask import Flask, jsonify

books = {
    "1984": "George Orwell",
    "To Kill a Mockingbird": "Harper Lee",
    "The Great Gatsby": "F. Scott Fitzgerald"
}

api_prefix = "/api"

app = Flask(__name__)

@app.route(f"{api_prefix}/books")
def get_books():
    return jsonify(books)

# Add the code to run the app with debug=True
# Your code here

Need a hint?

Use the standard Flask pattern to run the app only when the script is executed directly.