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Use FastAPI's lifespan context manager to create and dispose shared clients or pools once at startup and shutdown, expose them via app.state, and keep request-scoped cleanup in dependencies with yield.
Learn why the FastAPI lifespan context manager is the preferred choice over deprecated on_event handlers for managing async startup and shutdown resources.
FastAPI's lifespan context manager replaces deprecated on_event handlers for startup/shutdown. Learn how to share a single pooled httpx.AsyncClient across requests, wire it through dependency injection, and avoid common testing pitfalls.
Learn how FastAPI’s lifespan event handler centralises startup and shutdown logic, with a worked example using a SQLAlchemy async connection pool and notes on version and server requirements.
Choose FastAPI's lifespan context manager over legacy on_event handlers for reliable startup/shutdown of database pools, caches, and telemetry. This guide compares mechanisms, shows a production-ready pattern with nested async context managers, and provides validation steps.
Use FastAPI lifespan context managers to initialize app-scoped resources once at startup and guarantee cleanup on shutdown, exposing them via dependency injection without globals.
Compare FastAPI's lifespan context manager with legacy on_event hooks. Learn how to safely initialize DB pools and shared resources using app.state for better testability and ASGI compliance.
FastAPI utilizes the lifespan context manager to handle application startup and shutdown logic. This mechanism allows developers to manage resources like database connection pools or HTTP clients across the entire application lifecycle. While the startup phase is straightforward, the shutdown phase lacks a built-in framework constraint to enforce a maximum e
The goal is to configure application lifecycle handling so that monitoring alerts capture real startup and shutdown failures without generating noise from deprecation signals during a migration period. FastAPI 0.93 introduced the lifespan async context manager as the documented standard for startup and shutdown management, with @app.on_event("startup") and @
fastapi
python