python-fastapi-handler

Standardize async FastAPI route handlers by applying a thin-object pattern that enforces structural validation through Pydantic models before handler execution. This ensures only valid data reaches business logic, keeping request-response orchestration clean and consistent.

Centralized error mapping in FastAPI maps domain-specific exceptions to canonical HTTP status codes and error envelopes. This prevents internal implementation details from leaking to clients and eliminates inconsistent transport-layer code across your API.

Use FastAPI Depends for clean dependency injection to manage infrastructure concerns like database units of work and authentication. This keeps your API handlers focused solely on request-response orchestration rather than infrastructure setup.

This FastAPI handler pattern satisfies requirements for production-grade API transport layers using Pydantic v2 and asyncpg. It enforces strict contract adherence and clean dependency injection for backend service development.

The best way to prevent malformed requests from reaching FastAPI business logic is leveraging framework-level validation with Pydantic models. This rejects invalid data before handler execution, ensuring structural compliance and strict contract adherence.

You need a thin-handler pattern for production-ready FastAPI development when building backend services requiring strict contract adherence, centralized error mapping, and clean dependency injection to eliminate inconsistent transport-layer code.