Me too, but not until the last deployment. It was working fine before.

Hello vishal-parekh , i searched and i find that python3.13.11 has just released yesterday 5/12/2025

The problem is that mise doesn't have precompiled binaries for Python 3.13.11 yet because it hasn't been officially released. The error message confirms this: no precompiled python found for core:python@3.13.11 on x86_64-unknown-linux-gnu

you can change the 3.13.11 to a more stable one

Python releases by version number:

check this website : https://www.python.org/downloads/

How do I tell Railway which python version to use? I am still using 3.11. locally.

railway uses Nixpacks by default, which auto-detects Python version from this file :

use .python-versionfile :

# create a file named .python-version in your project root
echo "3.11.13" > .python-version

create a .python-version file with just 3.11.13 in it, Railway/Nixpacks will respect this

Thanks! Got it to work.

happy to hear that, what about you vishal-parekh ?

I didn't need to try that solution because when I re-ran the deploy this morning, the build was successful.

ok great , thanks for confirming the resolution! this helps document the fix for others :

so for anyone else hitting this error in the future:

if you get mise ERROR no precompiled python found for core:python@3.13.11

first try Redeploy/rebuild (this fixed it for vishal-parekh)

if that fails clear Railway's build cache or trigger a clean rebuild

if still failing check if the Python version exists and use .python-version file to specify an alternative

How is a build cache cleared ? I don't see in the option in the Railway settings...

railway does NOT have a "Clear Cache" button in the UI settings , but you can add NO_CACHE=1 to your service's environment variables, redeploy, and you're done

i hope this was helpful

Railway does not use Nixpacks by default. Nixpacks is deprecated and considered "legacy", and they suggest moving to their new system Railpack. Railpack is the default on all new services.

If you need to use a custom Python version, you can set the RAILPACK_PYTHON_VERSION environment variable on your service to the version you want to use. More info here: https://railpack.com/languages/python#versions

This is the correct response. And a better alternative to creating and maintaining a separate file just to reference a python version.

So your problem did get resolved?

By the way, if you are using a compiled version of python (not all versions of python are precompiled) it is not currently well supported. This is something on my TODO list and will be fixed soon! Sorry for the trouble here.