diff --git a/default.nix b/default.nix
index 4c3ae64..ef7bd2a 100644
--- a/default.nix
+++ b/default.nix
@@ -1,3 +1,5 @@
+# MIT License, see below
+#
 # These are some helpers for figuring out the derivations attributes of runtime
 # dependencies of a derivation, in particular the function `runtimeReport`. At
 # the bottom of the file you can see it used on `hello`. Spoiler: glibc is a
@@ -8,7 +10,7 @@
 
 # Let's call these "imports". They're functions used throughout the code.
 # Nothing interesting here.
-{ program, system, pkgs ? import <nixpkgs>{}}:
+{ drv, pkgs ? import <nixpkgs>{}}:
 with rec
   {
     inherit (pkgs)
@@ -91,6 +93,7 @@ runtimeReport = drv:
             unique_by(.path)
             # Then we map over each build-time derivation and use `select()`
             # to keep only the ones that show up in $runtime
+
           | map(    # this little beauty checks if "obj.path" is in "runtime"
                 select(. as $obj | $runtime | any(.[] | . == $obj.path))
               | .report)
@@ -189,4 +192,38 @@ cinfo = drv: runCommand "${drv.name}-cinfo"
       jq -c 'map(select( length > 0 ))' > $out
   '';
 
-in runtimeReport program
+in {
+  runtimeReport = runtimeReport drv;
+  buildtimeDerivations = runCommand "${drv.name}-build" {
+    big = builtins.toJSON (buildtimeDerivations drv);
+    passAsFile = ["big"];
+    buildInputs = [ pkgs.jq];
+    } ''
+      cp $bigPath $out
+    '';
+  # let result = buildtimeDerivations drv;
+  #   in result;
+}
+
+# MIT License
+#
+# Copyright (c) 2021 Nicolas Mattia
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in all
+# copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+# SOFTWARE.
+#
diff --git a/flake.lock b/flake.lock
index 495a9a8..c6957ba 100644
--- a/flake.lock
+++ b/flake.lock
@@ -1,6 +1,88 @@
 {
   "nodes": {
+    "flake-utils": {
+      "locked": {
+        "lastModified": 1623875721,
+        "narHash": "sha256-A8BU7bjS5GirpAUv4QA+QnJ4CceLHkcXdRp4xITDB0s=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "f7e004a55b120c02ecb6219596820fcd32ca8772",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    },
+    "nix-bundle": {
+      "inputs": {
+        "nixpkgs": "nixpkgs"
+      },
+      "locked": {
+        "lastModified": 1626704917,
+        "narHash": "sha256-cJ73kxY5ZCPWQeQZyCSdvkBqjqJkU5wgETBNaXfqF18=",
+        "owner": "matthewbauer",
+        "repo": "nix-bundle",
+        "rev": "223f4ffc4179aa318c34dc873a08cb00090db829",
+        "type": "github"
+      },
+      "original": {
+        "owner": "matthewbauer",
+        "repo": "nix-bundle",
+        "type": "github"
+      }
+    },
+    "nix-utils": {
+      "inputs": {
+        "flake-utils": "flake-utils",
+        "nixpkgs": "nixpkgs_2"
+      },
+      "locked": {
+        "lastModified": 1632973430,
+        "narHash": "sha256-9G8zo+0nfYAALV5umCyQR/2hVUFNH10JropBkyxZGGw=",
+        "owner": "juliosueiras-nix",
+        "repo": "nix-utils",
+        "rev": "b44e1ffd726aa03056db9df469efb497d8b9871b",
+        "type": "github"
+      },
+      "original": {
+        "owner": "juliosueiras-nix",
+        "repo": "nix-utils",
+        "type": "github"
+      }
+    },
     "nixpkgs": {
+      "locked": {
+        "lastModified": 1620055814,
+        "narHash": "sha256-8LEHoYSJiL901bTMVatq+rf8y7QtWuZhwwpKE2fyaRY=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "1db42b7fe3878f3f5f7a4f2dc210772fd080e205",
+        "type": "github"
+      },
+      "original": {
+        "id": "nixpkgs",
+        "ref": "nixos-20.03-small",
+        "type": "indirect"
+      }
+    },
+    "nixpkgs_2": {
+      "locked": {
+        "lastModified": 1629252929,
+        "narHash": "sha256-Aj20gmGBs8TG7pyaQqgbsqAQ6cB+TVuL18Pk3DPBxcQ=",
+        "owner": "nixos",
+        "repo": "nixpkgs",
+        "rev": "3788c68def67ca7949e0864c27638d484389363d",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nixos",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "nixpkgs_3": {
       "locked": {
         "lastModified": 1634782485,
         "narHash": "sha256-psfh4OQSokGXG0lpq3zKFbhOo3QfoeudRcaUnwMRkQo=",
@@ -15,7 +97,9 @@
     },
     "root": {
       "inputs": {
-        "nixpkgs": "nixpkgs"
+        "nix-bundle": "nix-bundle",
+        "nix-utils": "nix-utils",
+        "nixpkgs": "nixpkgs_3"
       }
     }
   },
diff --git a/flake.nix b/flake.nix
index de1b72b..dbbf4eb 100644
--- a/flake.nix
+++ b/flake.nix
@@ -1,29 +1,57 @@
 {
-  description = "nix-generators";
+  description = "Example bundlers";
 
   inputs.nix-utils.url = "github:juliosueiras-nix/nix-utils";
-  outputs = { self, nixpkgs, nix-utils }: {
+  inputs.nix-bundle.url = "github:matthewbauer/nix-bundle";
 
-    defaultBundler = self.bundlers.toReport;
+  outputs = { self, nixpkgs, nix-bundle, nix-utils }: let
+      # System types to support.
+      supportedSystems = [ "x86_64-linux" "x86_64-darwin" "aarch64-linux" "aarch64-darwin" ];
 
-    bundlers = let
-      prog = program: with program; "${outPath}/bin/${if meta?mainProgram then meta.mainProgram else (builtins.parseDrvName name).name}";
-    in {
+      # Helper function to generate an attrset '{ x86_64-linux = f "x86_64-linux"; ... }'.
+      forAllSystems = nixpkgs.lib.genAttrs supportedSystems;
 
-      toRPM = {program,system}: nix-utils.bundlers.rpm {inherit system; program=prog program;};
+      # Nixpkgs instantiated for supported system types.
+      nixpkgsFor = forAllSystems (system: import nixpkgs { inherit system; });
 
-      toDEB = {program,system}: nix-utils.bundlers.deb {inherit system; program=prog program;};
+      # Backwards compatibility helper for previous bundler API
+      program = p: with p; "${outPath}/bin/${
+        if meta?mainProgram then
+          meta.mainProgram
+        else
+          (builtins.parseDrvName name).name
+      }";
+  in {
 
-      toDockerImage = {program, system}: nixpkgs.legacyPackages.${system}.dockerTools.buildLayeredImage {
-        name = program.name;
-        tag = "latest";
-        contents = [ program ];
+    # defaultBundler.x86_64-linux = forAllSystems (system: self.bundlers.${system}.toArx);
+    defaultBundler.x86_64-linux = self.bundlers.x86_64-linux.toArx;
+
+    bundlers = forAllSystems (system: {
+      toArx = drv: nix-bundle.bundlers.nix-bundle {inherit system; program=program drv;};
+
+      toRPM = drv: nix-utils.bundlers.rpm {inherit system; program=program drv;};
+
+      toDEB = drv: nix-utils.bundlers.deb {inherit system; program=program drv;};
+
+      toDockerImage = drv:
+        nixpkgs.legacyPackages.${system}.dockerTools.buildLayeredImage {
+          name = drv.name;
+          tag = "latest";
+          contents = [ drv ];
       };
 
-      toReport = {program, system}:
-        import ./default.nix {
-          inherit program system;
-          pkgs = nixpkgs.legacyPackages.${system};};
-        };
-    };
+      toBuildDerivation = drv:
+        (import ./default.nix {
+          inherit drv;
+          pkgs = nixpkgsFor.${system};}).buildtimeDerivations;
+
+      toReport = drv:
+         builtins.trace drv
+        (import ./default.nix {
+          inherit drv;
+          pkgs = nixpkgsFor.${system};}).runtimeReport;
+
+      identity = drv: drv;
+    });
+  };
 }