prefer-remote-fetch is an overlay that download sources on remote builder. This is useful when the evaluating machine has a slow upload while the builder can fetch faster directly from the source. To use it, put the following snippet as a new overlay: self: super: (super.prefer-remote-fetch self super) A full configuration example for that sets the overlay up for your own account, could look like this $ mkdir ~/.config/nixpkgs/overlays/ $ cat > ~/.config/nixpkgs/overlays/prefer-remote-fetch.nix <<EOF self: super: super.prefer-remote-fetch self super EOF