For things in nixpkgs, the files will be mirrored on the nix cache. For your own stuff you could set up your own cache or use a service like cachix. There is al

For things in nixpkgs, the files will be mirrored on the nix cache. For your own stuff you could set up your own cache or use a service like cachix. There is also a nix option to set up a generic mirror which looks up files by hash, but I'm not sure if it works with all the ways to fetch things: https://nixos.org/manual/nix/stable/command-ref/conf-file#conf-hashed-mirrors https://nixos.org/manual/nix/stable/command-ref/conf-file#co...