{
  description = ''
    specimen, application and server configuration.
    enjoy! :)
  '';

  inputs = {
    nixpkgs.url = "github:nixos/nixpkgs?ref=nixos-unstable";
  };

  outputs =
    inputs@{ self, nixpkgs }:
    let
      inherit (nixpkgs) lib;

      name = "specimen";
      systems = [
        "x86_64-linux"
        "aarch64-linux"
      ];

      pkgsForSystem = system: import nixpkgs { inherit system; };

      forAllSystems =
        f:
        lib.genAttrs systems (
          system:
          f {
            inherit system;
            pkgs = pkgsForSystem system;
          }
        );
    in
    {
      packages = forAllSystems (
        { system, pkgs }:
        {
          default = pkgs.callPackage ./application/. { };
        }
      );

      devShells = forAllSystems (
        { system, pkgs }:
        {
          default = pkgs.mkShell {
            buildInputs = with pkgs; [
              go
              gopls
              delve
              go-task
              golangci-lint
            ];
          };
        }
      );

      nixosModules.default = import ./application/module.nix;

      nixosConfigurations.${name} = lib.nixosSystem {
        system = "aarch64-linux";
        specialArgs = inputs;
        modules = [
          ./configuration/configuration.nix
          self.nixosModules.default
        ];
      };
    };
}