diff --git a/lib/flake.nix b/lib/flake.nix
index 9025477a..17e069c2 100644
--- a/lib/flake.nix
+++ b/lib/flake.nix
@@ -35,7 +35,6 @@
               inherit deploy;
             };
             evalArgs = import ./mkFlake/evalArgs.nix { lib = nixpkgs.lib // self; };
-            evalOldArgs = import ./mkFlake/evalOldArgs.nix { lib = nixpkgs.lib // self; };
           };
 
           pkgs-lib = import ./pkgs-lib {
@@ -83,7 +82,7 @@
           mkFlakeDoc = pkgs.writeText "mkFlakeOptions.md"
             (
               pkgs.nixosOptionsDoc {
-                inherit (lib.mkFlake.evalArgs { nixos = "nixos"; args = { }; }) options;
+                inherit (lib.mkFlake.evalArgs { args = { }; }) options;
               }
             ).optionsMDDoc;
         };
diff --git a/lib/mkFlake/default.nix b/lib/mkFlake/default.nix
index d086283a..3d285c73 100644
--- a/lib/mkFlake/default.nix
+++ b/lib/mkFlake/default.nix
@@ -1,64 +1,85 @@
 { lib, deploy }:
 let
   inherit (lib) os;
+  inherit (builtins) mapAttrs attrNames attrValues head isFunction;
 in
 
-_: { self, inputs, nixos, ... } @ args:
+_: { self, inputs, ... } @ args:
 let
 
-  cfg = (
-    lib.mkFlake.evalOldArgs
-      { inherit self inputs args; }
-  ).config;
-
-  multiPkgs = os.mkPkgs
-    {
-      inherit self inputs nixos;
-      inherit (cfg) extern overrides;
-    };
-
-  outputs = {
-    nixosConfigurations = os.mkHosts
-      {
-        inherit self inputs nixos multiPkgs;
-        inherit (cfg) extern suites overrides;
-        dir = cfg.hosts;
-      };
-
-    homeConfigurations = os.mkHomeConfigurations self.nixosConfigurations;
-
-    nixosModules = cfg.modules;
-
-    homeModules = cfg.userModules;
-
-    overlay = cfg.packages;
-    inherit (cfg) overlays;
-
-    deploy.nodes = os.mkNodes deploy self.nixosConfigurations;
+  config = lib.mkFlake.evalArgs {
+    args = lib.mkMerge [ args { _module.check = false; } ];
   };
 
-  systemOutputs = lib.eachDefaultSystem (system:
-    let
-      pkgs = multiPkgs.${system};
-      pkgs-lib = lib.pkgs-lib.${system};
-      # all packages that are defined in ./pkgs
-      legacyPackages = os.mkPackages {
-        inherit pkgs;
-        inherit (self) overlay overlays;
-      };
-    in
-    {
-      checks = pkgs-lib.tests.mkChecks {
+  cfg = config.config;
+
+  otherArguments = removeAttrs args (attrNames config.options);
+
+  defaultModules = with lib.modules; [
+    (hmDefaults {
+      inherit (cfg.home) suites;
+      modules = cfg.home.modules ++ cfg.home.externalModules;
+    })
+    (globalDefaults {
+      inherit self inputs;
+    })
+  ];
+
+  getDefaultChannel = channels: channels.${cfg.nixos.hostDefaults.channelName};
+in
+lib.systemFlake (lib.recursiveUpdate
+  otherArguments
+  {
+    inherit self inputs;
+    inherit (cfg) channelsConfig supportedSystems;
+
+    mkFlakeConfig = config;
+
+    channels = mapAttrs
+      (name: channel:
+        channel // {
+          # pass channels if "overlay" has three arguments
+          overlaysBuilder = channels: lib.unifyOverlays channels channel.overlays;
+        }
+      ) cfg.channels;
+
+    # the host arguments cannot exist for fup hostDefaults to work
+    # so evalArgs sets them to null by default and the null args are filtered out here
+    hosts = mapAttrs (_: host: lib.filterAttrs (_: arg: arg != null) host) cfg.nixos.hosts;
+
+    hostDefaults = {
+      specialArgs.suites = cfg.nixos.suites;
+      modules = cfg.nixos.hostDefaults.modules
+        ++ cfg.nixos.hostDefaults.externalModules
+        ++ defaultModules;
+      builder = os.devosSystem { inherit self inputs; };
+      inherit (cfg.nixos.hostDefaults)
+        channelName
+        system;
+    };
+
+    nixosModules = lib.exporter.modulesFromList cfg.nixos.hostDefaults.modules;
+
+    homeModules = lib.exporter.modulesFromList cfg.home.modules;
+    homeConfigurations = os.mkHomeConfigurations self.nixosConfigurations;
+
+    deploy.nodes = os.mkNodes deploy self.nixosConfigurations;
+
+    overlays = lib.exporter.overlaysFromChannelsExporter { inherit (self) pkgs inputs; };
+
+    packagesBuilder = lib.builder.packagesFromOverlaysBuilderConstructor self.overlays;
+
+    checksBuilder = channels:
+      lib.pkgs-lib.tests.mkChecks {
+        pkgs = getDefaultChannel channels;
         inherit (self.deploy) nodes;
         hosts = self.nixosConfigurations;
         homes = self.homeConfigurations;
       };
 
-      inherit legacyPackages;
-      packages = lib.filterPackages system legacyPackages;
-
-      devShell = pkgs-lib.shell;
-    });
-in
-outputs // systemOutputs
-
+    devShellBuilder = channels:
+      lib.pkgs-lib.shell {
+        pkgs = getDefaultChannel channels;
+      };
+  }
+)
diff --git a/lib/mkFlake/evalOldArgs.nix b/lib/mkFlake/evalOldArgs.nix
deleted file mode 100644
index c319d43a..00000000
--- a/lib/mkFlake/evalOldArgs.nix
+++ /dev/null
@@ -1,162 +0,0 @@
-{ lib }:
-
-{ self, inputs, args }:
-let
-  argOpts = with lib; { config, options, ... }:
-    let
-      inherit (lib) os;
-
-      inherit (config) self;
-
-      inputAttrs = with types; functionTo attrs;
-      moduleType = with types; anything // {
-        inherit (submodule { }) check;
-        description = "valid module";
-      };
-    in
-    {
-      options = with types; {
-        self = mkOption {
-          type = addCheck attrs lib.isStorePath;
-          description = "The flake to create the devos outputs for";
-        };
-        nixos = mkOption {
-          type = addCheck attrs lib.isStorePath;
-          description = "The default nixpkgs channel of the devos";
-        };
-        inputs = mkOption {
-          type = addCheck attrs lib.isStorePath;
-          description = "All inptus of the devos";
-        };
-        hosts = mkOption {
-          type = path;
-          default = "${self}/hosts";
-          defaultText = "\${self}/hosts";
-          apply = toString;
-          description = ''
-            Path to directory containing host configurations that will be exported
-            to the 'nixosConfigurations' output.
-          '';
-        };
-        packages = mkOption {
-          # functionTo changes arg names which breaks flake check
-          type = types.anything // {
-            check = builtins.isFunction;
-            description = "Nixpkgs overlay";
-          };
-          default = (final: prev: { });
-          defaultText = "(final: prev: {})";
-          description = ''
-            Overlay for custom packages that will be included in treewide 'pkgs'.
-            This should follow the standard nixpkgs overlay format - two argument function
-            that returns an attrset.
-            These packages will be exported to the 'packages' and 'legacyPackages' outputs.
-          '';
-        };
-        modules = mkOption {
-          type = listOf moduleType;
-          default = [ ];
-          apply = lib.pathsToImportedAttrs;
-          description = ''
-            list of modules to include in confgurations and export in 'nixosModules' output
-          '';
-        };
-        userModules = mkOption {
-          type = listOf moduleType;
-          default = [ ];
-          apply = lib.pathsToImportedAttrs;
-          description = ''
-            list of modules to include in home-manager configurations and export in
-            'homeModules' output
-          '';
-        };
-        profiles = mkOption {
-          type = path;
-          default = "${self}/profiles";
-          defaultText = "\${self}/profiles";
-          apply = x: os.mkProfileAttrs (toString x);
-          description = "path to profiles folder that can be collected into suites";
-        };
-        userProfiles = mkOption {
-          type = path;
-          default = "${self}/users/profiles";
-          defaultText = "\${self}/users/profiles";
-          apply = x: os.mkProfileAttrs (toString x);
-          description = "path to user profiles folder that can be collected into userSuites";
-        };
-        suites =
-          let
-            defaults = { user = { }; system = { }; };
-          in
-          mkOption {
-            type = inputAttrs;
-            default = { ... }: defaults;
-            defaultText = "{ user = {}; system = {}; }";
-            apply = suites: defaults // os.mkSuites {
-              inherit suites;
-              inherit (config) profiles users userProfiles;
-            };
-            description = ''
-              Function with inputs 'users' and 'profiles' that returns attribute set
-              with user and system suites. The former for Home Manager and the latter
-              for nixos configurations.
-              These can be accessed through the 'suites' specialArg in each config system.
-            '';
-          };
-        users = mkOption {
-          type = path;
-          default = "${self}/users";
-          defaultText = "\${self}/users";
-          apply = x: os.mkProfileAttrs (toString x);
-          description = ''
-            path to folder containing profiles that define system users
-          '';
-        };
-        extern =
-          let
-            defaults = {
-              modules = [ ];
-              overlays = [ ];
-              specialArgs = { };
-              userModules = [ ];
-              userSpecialArgs = { };
-            };
-          in
-          mkOption {
-            type = inputAttrs;
-            default = { ... }: defaults;
-            defaultText = ''
-              { modules = []; overlays = []; specialArgs = []; userModules = []; userSpecialArgs = []; }
-            '';
-            # So unneeded extern attributes can safely be deleted
-            apply = x: defaults // (x { inputs = inputs // self.inputs; });
-            description = ''
-              Function with argument 'inputs' that contains all devos and ''${self}'s inputs.
-              The function should return an attribute set with modules, overlays, and
-              specialArgs to be included across nixos and home manager configurations.
-              Only attributes that are used should be returned.
-            '';
-          };
-        overlays = mkOption {
-          type = path;
-          default = "${self}/overlays";
-          defaultText = "\${self}/overlays";
-          apply = x: lib.pathsToImportedAttrs (lib.pathsIn (toString x));
-          description = ''
-            path to folder containing overlays which will be applied to pkgs and exported in
-            the 'overlays' output
-          '';
-        };
-        overrides = mkOption rec {
-          type = attrs;
-          default = { modules = [ ]; disabledModules = [ ]; packages = _: _: _: { }; };
-          defaultText = "{ modules = []; disabledModules = []; packages = {}; }";
-          apply = x: default // x;
-          description = "attrset of packages and modules that will be pulled from nixpkgs master";
-        };
-      };
-    };
-in
-lib.evalModules {
-  modules = [ argOpts args ];
-}