Route decorator syntax in FastAPI - Mini Project: Build & Apply

Route decorator syntax

📖 Scenario: You are building a simple web API using FastAPI. You want to create routes that respond to HTTP requests.

🎯 Goal: Create a FastAPI app with a route that responds to GET requests at the path /hello and returns a greeting message.

📋 What You'll Learn

Create a FastAPI app instance named app

Define a route using the @app.get decorator for the path /hello

Create a function named hello that returns the string 'Hello, FastAPI!'

💡 Why This Matters

🌍 Real World

Web APIs use route decorators to define how the server responds to different URLs and HTTP methods.

💼 Career

Understanding route decorators is essential for backend developers working with FastAPI or similar web frameworks.

1

Create FastAPI app instance

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

FastAPI

from fastapi import FastAPI

# Create the FastAPI app instance named app
# Your code here

Need a hint?

Use app = FastAPI() to create the app instance.

2

Add GET route decorator

Use the @app.get decorator with the path "/hello" above a function named hello.

FastAPI

from fastapi import FastAPI

app = FastAPI()

# Add @app.get decorator for path '/hello' above the hello function
# Your code here

Need a hint?

Write @app.get("/hello") just before defining def hello():.

3

Return greeting message

Inside the hello function, return the string 'Hello, FastAPI!'.

FastAPI

from fastapi import FastAPI

app = FastAPI()

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

Need a hint?

Use return 'Hello, FastAPI!' inside the function.

4

Complete FastAPI route setup

Ensure the full code includes the import, app creation, route decorator, and function returning the greeting.

FastAPI

from fastapi import FastAPI

app = FastAPI()

@app.get("/hello")
def hello():
    return 'Hello, FastAPI!'

# Code complete

Need a hint?

Review the full code to confirm all parts are present.