Code Mala Tang

Jun 2, 2025 · Backend Development

Unlocking FastAPI: A Deep Dive into Starlette, ASGI, and Middleware Architecture

This article explains how FastAPI builds on Starlette, covering the ASGI protocol, Starlette's initialization, middleware design—including ExceptionMiddleware and user-defined middleware—and routing mechanisms, while providing concrete code examples and performance insights for backend developers.