{
  description = "small utilities";

  inputs = {
    nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable";
    nim2nix.url = "github:daylinmorgan/nim2nix";
    nim2nix.inputs.nixpkgs.follows = "nixpkgs";
  };

  outputs =
    { nixpkgs, nim2nix, ... }:
    let
      inherit (nixpkgs.lib) genAttrs;
      systems = [
        "x86_64-linux"
        "x86_64-darwin"
        "aarch64-linux"
        "aarch64-darwin"
      ];
      forAllSystems =
        f:
        genAttrs systems (
          system:
          f (
            import nixpkgs {
              inherit system;
              overlays = [ nim2nix.overlays.default ];
            }
          )
        );
    in
    {
      packages = forAllSystems (pkgs: rec {
        utils = pkgs.callPackage ./meta.nix { inherit tunnel; };
        tunnel-go = pkgs.callPackage ./tunnel-go { };
        tunnel-nim = pkgs.callPackage ./tunnel-nim { };
        tunnel = tunnel-nim;
        default = utils;
      });
      devShells = forAllSystems (pkgs: {
        default = pkgs.mkShell {
          packages = with pkgs; [
            go
            nim
          ];
        };
      });
      formatter = forAllSystems (pkgs: pkgs.nixfmt-rfc-style);
    };
}