First FastAPI application - Mini Project: Build & Apply

First FastAPI application

📖 Scenario: You want to create a simple web API that responds with a greeting message. This is useful when you want to start learning how to build web services that can be accessed from browsers or other programs.

🎯 Goal: Build a basic FastAPI application that has one route / which returns a JSON response with a greeting message.

📋 What You'll Learn

Create a FastAPI app instance named app

Define a GET route for path /

The route function should be named read_root

The route should return a dictionary with key message and value Hello, FastAPI!

💡 Why This Matters

🌍 Real World

FastAPI is used to build fast and modern web APIs that can serve data to web apps, mobile apps, or other services.

💼 Career

Knowing how to create basic FastAPI apps is essential for backend developers working with Python to build scalable APIs.

1

Create FastAPI app instance

Import FastAPI from fastapi and create an app instance called app.

FastAPI

# Import FastAPI and create app instance
# Your code here

Need a hint?

Use from fastapi import FastAPI and then app = FastAPI().

2

Define GET route for root path

Use the @app.get("/") decorator to define a GET route for the root path /.

FastAPI

from fastapi import FastAPI

app = FastAPI()

# Define GET route for path '/' here
# Your code here

Need a hint?

Use @app.get("/") above a function named read_root.

3

Return greeting message from route

Inside the read_root function, return a dictionary with key message and value Hello, FastAPI!.

FastAPI

from fastapi import FastAPI

app = FastAPI()

@app.get("/")
def read_root():
    # Return greeting message here
    # Your code here

Need a hint?

Return a dictionary like {"message": "Hello, FastAPI!"}.

4

Complete FastAPI app

Ensure the full code has the import, app instance, route decorator, function read_root, and the return statement with the greeting message.

FastAPI

from fastapi import FastAPI

app = FastAPI()

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

# Your code here if needed

Need a hint?

Check that all parts are present: import, app, route, function, and return.