{
  description = "A webserver to create files for tetsing purposes";

  inputs = {
    nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable";
    poetry2nix-lib = {
      url = "github:nix-community/poetry2nix";
      inputs.nixpkgs.follows = "nixpkgs";
    };
    microvm = {
      url = "github:astro/microvm.nix";
      inputs.nixpkgs.follows = "nixpkgs";
    };
  };

  outputs = {self, ...} @ inputs: let
    supportedSystems = ["x86_64-linux" "x86_64-darwin" "aarch64-linux" "aarch64-darwin"];
    forAllSystems = inputs.nixpkgs.lib.genAttrs supportedSystems;
    pkgs = forAllSystems (system: inputs.nixpkgs.legacyPackages.${system});
    poetry2nix = forAllSystems (system: inputs.poetry2nix-lib.lib.mkPoetry2Nix {pkgs = pkgs.${system};});

    addSetuptools = self: super: list:
      builtins.listToAttrs (builtins.map (package: {
          name = "${package}";
          value = super."${package}".overridePythonAttrs (old: {
            nativeBuildInputs = (old.nativeBuildInputs or []) ++ [self.setuptools];
          });
        })
        list);
  in {
    # `nix build`
    packages = forAllSystems (system: let
      mkPackage = {debug ? false}:
        poetry2nix.${system}.mkPoetryApplication {
          projectDir = self;
          checkPhase =
            if debug
            then "pyright --warnings testdata && pytest"
            else "";
          # doCheck = debug;
          preferWheels = false;
          nativeBuildInputs = with pkgs.${system}; [pyright];
          overrides =
            poetry2nix.${system}.overrides.withDefaults (self: super:
              addSetuptools self super ["sqlite-minutils" "fastlite" "python-fasthtml"]);
        };
    in {
      default = mkPackage {debug = false;};
      debug = mkPackage {debug = true;};
      vm = self.nixosConfigurations.vm.config.microvm.declaredRunner;
    });

    # `nix run`
    apps = forAllSystems (system: {
      default = {
        program = "${self.packages.${system}.default}/bin/testdata";
        type = "app";
      };
    });

    # `nix fmt`
    formatter = forAllSystems (system: pkgs.${system}.alejandra);

    # `nix develop`
    devShells = forAllSystems (system: {
      # Shell for app dependencies.
      #
      #     nix develop
      #
      # Use this shell for developing your app.
      default = pkgs.${system}.mkShellNoCC {
        inputsFrom = [self.packages.${system}.default];
        packages = [self.packages.${system}.default];
      };

      # Shell for poetry.
      #
      #     nix develop .#poetry
      #
      # Use this shell for changes to pyproject.toml and poetry.lock.
      poetry = pkgs.${system}.mkShellNoCC {
        packages = [pkgs.${system}.poetry];
      };
    });

    # NixOS Module
    nixosModules.default = import ./nix/module.nix inputs;
  };
}