I use this for building system. Instead of Cachix I just set it up as an S3 bucket (it's a bit involving but also works). I needed to tweak some things but ulti

I use this for building system. Instead of Cachix I just set it up as an S3 bucket (it's a bit involving but also works). I needed to tweak some things but ultimately arrived to satisfying results. The nice thing is that it sped up building by 50% and also extra bonus with things is that with merges, if files didn't change nix will finish building instantaneously. This is similar with nix-shell, where for example with python you enter "virtualenv" like environment almost instantly without downloading dependencies over and over. Yes, you could get close to do that with CI by using some caching, but this is out of the box, due to nix understanding dependencies. Also another great thing is that so far, I never needed to purge cache, which often happens with normal CI caching.