Starlette End of Life - Dates and Lifecycle

Starlette is a lightweight ASGI framework and toolkit for building asynchronous Python web services, providing routing, request and response handling, WebSocket support, and middleware. It's best known as the foundation FastAPI is built on top of, which means most FastAPI users are running Starlette underneath without necessarily tracking it as a separate dependency.

Starlette Lifecycle Explained

Starlette has no formal, scheduled end of life policy, and for most of its life it didn't even have a stable release to build one around. Created in June 2018, it stayed on ZeroVer (0.x) versioning for almost eight years before finally reaching its first stable 1.0.0 release in March 2026. Like other Pallets-adjacent and single-maintainer Python libraries, only the current release is meaningfully supported, once a new version ships, the previous one is effectively retired with no guaranteed backport of fixes, security issues included.

That said, real end of life events do happen, they're just driven by supersession rather than a calendar. New releases have periodically dropped support for older Python versions in step with Python's own lifecycle: 0.20.0 dropped Python 3.6, 0.30.0 dropped Python 3.7, 0.45.0 dropped Python 3.8, and 0.50.0 dropped Python 3.9. An old pinned Starlette version can silently cap which Python release you're able to run.

Security patches have been infrequent but real: a path traversal vulnerability in StaticFiles was fixed in 0.27.0 (2023), a denial-of-service issue in multipart form parsing was fixed in 0.40.0 (2024), and a Range header parsing vulnerability in FileResponse was fixed in 0.49.1 (2025). None of these were backported to older release lines, consistent with Starlette's practice of only patching forward.