diff --git a/all-modules.nix b/all-modules.nix
index 2ecd28c4..03439a03 100644
--- a/all-modules.nix
+++ b/all-modules.nix
@@ -6,6 +6,7 @@
./modules/darwinModules.nix
./modules/devShells.nix
./modules/flake.nix
+ ./modules/formatter.nix
./modules/legacyPackages.nix
./modules/moduleWithSystem.nix
./modules/nixosConfigurations.nix
diff --git a/modules/formatter.nix b/modules/formatter.nix
new file mode 100644
index 00000000..a63a9bab
--- /dev/null
+++ b/modules/formatter.nix
@@ -0,0 +1,55 @@
+{ config, lib, flake-parts-lib, ... }:
+let
+ inherit (lib)
+ filterAttrs
+ mapAttrs
+ mkOption
+ optionalAttrs
+ types
+ ;
+ inherit (flake-parts-lib)
+ mkSubmoduleOptions
+ mkPerSystemOption
+ ;
+in
+{
+ options = {
+ flake = mkSubmoduleOptions {
+ formatter = mkOption {
+ type = types.lazyAttrsOf types.package;
+ default = { };
+ description = ''
+ Per system package used by nix fmt.
+ '';
+ };
+ };
+
+ perSystem = mkPerSystemOption ({ config, ... }: {
+ _file = ./formatter.nix;
+ options = {
+ formatter = mkOption {
+ type = types.nullOr types.package;
+ default = null;
+ description = ''
+ A package used by nix fmt.
+ '';
+ };
+ };
+ });
+ };
+ config = {
+ flake.formatter =
+ mapAttrs
+ (k: v: v.formatter)
+ (filterAttrs
+ (k: v: v.formatter != null)
+ config.allSystems
+ );
+
+ perInput = system: flake:
+ optionalAttrs (flake?formatter.${system}) {
+ formatter = flake.formatter.${system};
+ };
+
+ };
+}