Python 3.13 freethreaded builds are not currently supported by Railpack, as Railpack uses Mise for Python installation and the freethreaded variant requires a different build configuration. Your latest deployment's runtime logs show Uvicorn running successfully on port 8080, so your current (non-freethreaded) build is working. If you specifically need freethreaded Python, you can use a custom Dockerfile to control the Python installation, or file an issue on the Railpack repo to request freethreaded support.

We've just fixed this issue! The problem was related to Mise python installs and Railack now has the fix from https://github.com/jdx/mise/releases/tag/v2026.3.10