I would be most grateful for any tips. Thanks

When I need to precompile something, generally when I use graalVM I use github action to be able to carry out that process and through the railway cli I deploy it to my project, perhaps this idea will be useful to you

Thank you so much, @ALoUnder! Hadn't thought about github actions, I'll give that a try.

Github actions didn't work for me. In the end I used this Dockerfile, and that seems to work very well.
I have a question, though. How do I know whether the default Dockerfile does something that mine does not? Is it possible to see that original Dockerfile somewhere?
Thanks anyone for any pointer.

You can check the build logs to see what it bundled with your image or you can download Nixpacks/Railpack CLI locally and run it in your project to see the Dockerfile it generates

!s