Block 67: FastAPI: Pydantic Models & Validation
Use Pydantic models to validate request and response data automatically.
Concepts
- from pydantic import BaseModel
- Defining request body models with type annotations
- Automatic validation and error messages
- Response models: response_model parameter
Code Examples
See exercise below.
Exercise
Define a Student model with name (str), age (int, min 0), grade (float, 0–100). POST endpoint that returns the validated student. Test with invalid data and observe FastAPI's automatic error responses.
Homework
What is the advantage of Pydantic validation over manually checking request data in Flask?