Request body declaration in FastAPI - Mini Project: Build & Apply

Request Body Declaration in FastAPI

📖 Scenario: You are building a simple API to receive user information for a newsletter subscription.The API should accept user data in the request body and process it.

🎯 Goal: Build a FastAPI endpoint that declares a request body using a Pydantic model to receive user data.

📋 What You'll Learn

Create a Pydantic model named User with fields name (string) and email (string).

Create a FastAPI app instance named app.

Create a POST endpoint at /subscribe that accepts a User object as the request body.

Return the received user data as JSON in the response.

💡 Why This Matters

🌍 Real World

APIs often need to receive structured data from clients. Declaring request bodies clearly helps validate and process this data safely.

💼 Career

Knowing how to declare request bodies with Pydantic models in FastAPI is essential for backend developers building modern web APIs.

1

Create the User model

Create a Pydantic model called User with two fields: name of type str and email of type str.

FastAPI

# Your code here
from pydantic import BaseModel

# Define User model

Need a hint?

Use class User(BaseModel): and define name and email as string fields.

2

Create the FastAPI app instance

Import FastAPI and create an app instance named app.

FastAPI

from fastapi import FastAPI

# Your code here

# Create FastAPI app instance

Need a hint?

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

3

Create the POST endpoint with request body

Create a POST endpoint at /subscribe using @app.post("/subscribe"). Define a function subscribe that takes a parameter user of type User to receive the request body.

FastAPI

@app.post("/subscribe")
# Your code here

# Define subscribe function with User parameter

Need a hint?

Use @app.post("/subscribe") decorator and define subscribe(user: User) function that returns user.

4

Complete the FastAPI app

Ensure the full code includes the User model, the app instance, and the /subscribe POST endpoint returning the user data.

FastAPI

# Your code here to complete the app if needed

Need a hint?

Make sure all parts are included and correctly indented.