: Support for versions of packages (instead of Nix’s approximate versions) Smaller Builds : We’ve been able to reduce image sizes between 38% (Node) and 77% (Python), enabling faster deploys on Railway : We’ve been able to reduce image sizes between 38% (Node) and 77% (Python), enabling faster deploys on Railway Better caching: Railpack interfaces directly with BuildKit to control the layers and filesystem, resulting in more cache hits (with sharable caches across environments) The way Nixpacks uses Nix to pull in dependencies often results in massive image sizes with a single /nix/store layer ... all Nix and related packages and libraries needed for both the build and runtime are here.