{
  description = "A web service to evaluate DuckDuckGo-style bangs in search queries";

  inputs = {
    nixpkgs.url = "github:nixos/nixpkgs/nixpkgs-unstable";
    flake-utils.url = "github:numtide/flake-utils";
  };

  outputs = { self, flake-utils, nixpkgs }: {
    overlay = final: prev: {
      bang-evaluator = prev.buildGoModule {
        name = "bang-evaluator";

        src = self;

        subPackages = [ "." ];

        vendorHash = "sha256-w3mFra7Je+8qIDQMSyUYucoLZ6GtrZmr56O6xmihIYc=";

        preBuild = ''go generate ./...'';

        doCheck = false; # no tests (yet?)

        meta = with prev.lib; {
          license = licenses.mit;
          maintainer = with mainatiners; [ sbruder ];
        };
      };
    };

    nixosModules.bang-evaluator = {
      imports = [ ./module.nix ];

      nixpkgs.overlays = [
        self.overlay
      ];
    };
  } // flake-utils.lib.eachSystem [ "aarch64-linux" "x86_64-linux" ] (system:
    let
      pkgs = import nixpkgs { inherit system; overlays = [ self.overlay ]; };
    in
    rec {
      packages = {
        inherit (pkgs) bang-evaluator;
      };

      defaultPackage = packages.bang-evaluator;
      defaultApp = {
        type = "app";
        program = "${packages.bang-evaluator}/bin/evaluator";
      };

      checks = {
        integration-test = import ./test.nix {
          inherit nixpkgs system;
          inherit (self) nixosModules;
        };
      };

      # My hydra only has x86_64-linux builders
      hydraJobs = if pkgs.lib.elem system [ "x86_64-linux" ]
        then {
          build = defaultPackage;
          integration-test = checks.integration-test;
        }
        else { };
    });
}