> Since package builds of node/python/ruby packages depend on stuff outside of the package dir in the tree, you need that mapping between versions and commits.

> Since package builds of node/python/ruby packages depend on stuff outside of the package dir in the tree, you need that mapping between versions and commits. > Using nix without nixpkgs may be fine for more scoped use but seems hard to justify for a platform like Railway. Nixpkgs isn't all-or-nothing. You're right that Nixpkgs itself rarely packages more than one version of something, but the standard approach for "language package managers" is that you use a tool like crate2nix[0] which automatically generates pinned derivations for all of your dependencies.[1] For system dependencies which aren't covered by your language package manager.. you're basically in the same position as for something like Debian: you can either pull it from Nixpkgs (and give up control beyond "which Nixpkgs am I on?") or you can write/fork your own package. Or you can pull specific packages from specific Nixpkgs checkouts and splice them into your "main" Nixpkgs version as an overlay (though this is definitely getting into the Weird Territory(tm)). [0]: https://github.com/nix-community/crate2nix https://github.com/nix-community/crate2nix [1]: For example: https://github.com/stackabletech/secret-operator/blob/30f0eb787857b47b832ff0ed06553aa21316d100/Cargo.nix https://github.com/stackabletech/secret-operator/blob/30f0eb...