How does FastAPI handle serialization and validation of data?
FastAPI uses Pydantic for data serialization and validation. Pydantic models define the shape of incoming or outgoing data, ensuring type correctness. When a request is received, FastAPI validates the data against the model’s schema using Python’s built-in typing system.
If the data doesn’t match the schema, FastAPI automatically sends an error response detailing the issue. For valid data, it serializes into JSON format for HTTP responses. This process also works in reverse for incoming JSON data, deserializing it into Python objects.
