FastAPI End of Life - Dates and Lifecycle

FastAPI is a high-performance Python web framework for building APIs, using standard Python type hints and Pydantic for request validation, serialization, and automatic OpenAPI documentation. It's built on top of Starlette for the underlying ASGI handling, and it has become one of the most widely adopted Python web frameworks since its creation in December 2018.

FastAPI Lifecycle Explained

FastAPI has no formal end of life policy, and its own official documentation doesn't use that language at all, there's no announced support window, deprecation schedule, or security-only phase. Instead, FastAPI follows an explicit Semantic Versioning convention even while staying below version 1.0.0: PATCH releases (the last number, as in 0.112.3) are always bug fixes and non-breaking changes, while MINOR releases (the middle number, as in 0.112.0) can include breaking changes. FastAPI's own docs recommend pinning to a MINOR version range, such as fastapi>=0.112.0,<0.113.0, to get safe patch updates automatically while controlling when you take on breaking changes.

Notably, FastAPI explicitly advises against pinning Starlette separately, each FastAPI version is built against a specific compatible Starlette release, and letting FastAPI manage that dependency avoids version mismatches. This matters given Starlette's own release pace: Starlette reached its first stable 1.0.0 release in March 2026, while FastAPI itself, after roughly seven years of development, remains on 0.x versioning with no announced timeline for a 1.0 release.

Real security fixes do happen periodically, called out explicitly as "Security fixes" in the release notes for versions like 0.65.1, 0.65.2, and 0.109.1. As with Starlette, there's no guarantee these get backported to older MINOR lines, staying current within your pinned MINOR range is the only way to reliably receive them.