{
  inputs = {
    nixpkgs.url = "github:radvendii/nixpkgs/nixos_rebuild_tests";
    nixpkgs-latest.url = "github:nixos/nixpkgs";

    pixelfed = {
      url = "github:pixelfed/pixelfed?ref=v0.12.3";
      flake = false;
    };
  };

  outputs =
    {
      self,
      nixpkgs,
      nixpkgs-latest,
      pixelfed,
    }:
    let
      system = "x86_64-linux";
      lib = nixpkgs.lib;
      pkgs = nixpkgs.legacyPackages.${system};
      pkgsLatest = nixpkgs-latest.legacyPackages.${system};
      bleedingFediverseOverlay = (
        _: _: {
          pixelfed = pkgsLatest.pixelfed.overrideAttrs (old: {
            src = pixelfed;
            patches = (old.patches or [ ]) ++ [ ./fediversity/pixelfed-group-permissions.patch ];
          });
          ## TODO: give mastodon, peertube the same treatment
        }
      );
    in
    {
      nixosModules = {
        ## Bleeding-edge fediverse packages
        bleedingFediverse = {
          nixpkgs.overlays = [ bleedingFediverseOverlay ];
        };
        ## Fediversity modules
        fediversity = import ./fediversity;

        ## VM-specific modules
        interactive-vm = import ./vm/interactive-vm.nix;
        garage-vm = import ./vm/garage-vm.nix;
        mastodon-vm = import ./vm/mastodon-vm.nix;
        peertube-vm = import ./vm/peertube-vm.nix;
        pixelfed-vm = import ./vm/pixelfed-vm.nix;
      };

      nixosConfigurations = {
        mastodon = nixpkgs.lib.nixosSystem {
          inherit system;
          modules = with self.nixosModules; [
            bleedingFediverse
            fediversity
            interactive-vm
            garage-vm
            mastodon-vm
          ];
        };

        peertube = nixpkgs.lib.nixosSystem {
          inherit system;
          modules = with self.nixosModules; [
            bleedingFediverse
            fediversity
            interactive-vm
            garage-vm
            peertube-vm
          ];
        };

        pixelfed = nixpkgs.lib.nixosSystem {
          inherit system;
          modules = with self.nixosModules; [
            bleedingFediverse
            fediversity
            interactive-vm
            garage-vm
            pixelfed-vm
          ];
        };

        all = nixpkgs.lib.nixosSystem {
          inherit system;
          modules = with self.nixosModules; [
            bleedingFediverse
            fediversity
            interactive-vm
            garage-vm
            peertube-vm
            pixelfed-vm
            mastodon-vm
          ];
        };
      };

      checks.${system} = {
        mastodon-garage = import ./tests/mastodon-garage.nix { inherit pkgs self; };
        pixelfed-garage = import ./tests/pixelfed-garage.nix { inherit pkgs self; };
      };

      devShells.${system}.default = pkgs.mkShell {
        inputs = with pkgs; [ nil ];
        shellHook = self.checks.${system}.pre-commit.shellHook;
      };
    };
}