I love nix, but one problem with it is that you typically need to be all-in. When building software, this makes sense - Nix’s reproducibility only works if all your dependencies are themselves available within nix. But as a colleague casually suggested one day: shouldn’t it be possible to run nix-built software without installing nix?
That’s exactly what runix does: lets your users run nix software from any binary cache, without installing nix itself.
It differs from projects like nix-portable in that it doesn’t intend to be a full-blown nix installation, all it does is run nix software from a binary cache.