Unfree software

Per-package (Ideal)

This method works for NixOS system level configuration and Home-Manager standalone

{lib, ...}: {
  nixpkgs.config.allowUnfreePredicate = pkg:
    builtins.elem (lib.getName pkg) [
      # Add additional package names here
      "hello-unfree"
    ];
}

For all packages

This method works for NixOS system level configuration

{
  nixpkgs.config.allowUnfree = true;
}

This previous method should work for Home-Manager standalone but is currently broken see: Home-Manager Issue 2942 the work-around is using:

{
  nixpkgs.config.allowUnfreePredicate = _: true;
}

Imperative CLI

You won't be able to install or search for an unfree package as a user, unless you explicitly enable it in ~/.config/nixpkgs/config.nix (the file and folder may need to be created):

{
  allowUnfree = true;
}

Temporary allowing

For temporary allowing unfree packages you can set the environment variable NIXPKGS_ALLOW_UNFREE, e.g.

$ NIXPKGS_ALLOW_UNFREE=1 nix-shell

Note for nix3 commands you need to pass --impure as well

More precision

For whitelisting only specific unfree licenses see the "Installing unfree packages" section of the Nixpkgs manual.

Note that we are not able to test or build unfree software on Hydra due to policy. Most unfree licenses prohibit us from either executing or distributing the software.