diff --git a/modules/files.nix b/modules/files.nix
index 121b72e24..f1be39b83 100644
--- a/modules/files.nix
+++ b/modules/files.nix
@@ -55,6 +55,8 @@ let
         name = sourceName;
       };
 
+  putterStatePath = "${config.xdg.stateHome}/home-manager/putter-state.json";
+
 in
 
 {
@@ -88,11 +90,44 @@ in
       '';
     };
 
+    home.fileActivator = lib.mkOption {
+      type =
+        with lib.types;
+        enum [
+          "legacy"
+          "putter"
+        ];
+      default = "legacy";
+      example = "putter";
+      visible = false;
+      description = ''
+        The tooling to use to place files during activation.
+
+        The legacy option (currently the default) is the built-in tooling that
+        is very robust, but is limited in future potential.
+
+        The putter option is a new external tool that may replace the legacy
+        alternative in the future. It is not as hardened as the legacy
+        alternative but will allow future features such as file copying.
+
+        This option should be considered experimental and is therefore hidden
+        from documentation at this time.
+      '';
+    };
+
     home-files = lib.mkOption {
       type = lib.types.package;
       internal = true;
       description = "Package to contain all home files";
     };
+
+    home.internal = {
+      filePutterConfig = lib.mkOption {
+        type = lib.types.package;
+        internal = true;
+        description = "Putter configuration.";
+      };
+    };
   };
 
   config = {
@@ -149,21 +184,29 @@ in
 
         storeDir = lib.escapeShellArg builtins.storeDir;
 
-        check = pkgs.replaceVars ./files/check-link-targets.sh {
+        legacyCheckScript = pkgs.replaceVars ./files/check-link-targets.sh {
           inherit (config.lib.bash) initHomeManagerLib;
           inherit forcedPaths storeDir;
         };
-      in
-      ''
-        function checkNewGenCollision() {
-          local newGenFiles
-          newGenFiles="$(readlink -e "$newGenPath/home-files")"
-          find "$newGenFiles" \( -type f -or -type l \) \
-              -exec bash ${check} "$newGenFiles" {} +
-        }
 
-        checkNewGenCollision || exit 1
-      ''
+        legacyCheckLinkTargets = ''
+          function checkNewGenCollision() {
+            local newGenFiles
+            newGenFiles="$(readlink -e "$newGenPath/home-files")"
+            find "$newGenFiles" \( -type f -or -type l \) \
+                -exec bash ${legacyCheckScript} "$newGenFiles" {} +
+          }
+
+          checkNewGenCollision || exit 1
+        '';
+
+        putterCheckLinkTargets = ''
+          ${lib.getExe pkgs.putter} check $VERBOSE_ARG \
+            --state-file "${putterStatePath}" \
+            ${config.home.internal.filePutterConfig}
+        '';
+      in
+      if config.home.fileActivator == "putter" then putterCheckLinkTargets else legacyCheckLinkTargets
     );
 
     # This activation script will
@@ -186,7 +229,9 @@ in
     # source and target generation.
     home.activation.linkGeneration = lib.hm.dag.entryAfter [ "writeBoundary" ] (
       let
-        link = pkgs.writeShellScript "link" ''
+        storeDir = lib.escapeShellArg builtins.storeDir;
+
+        legacyLink = pkgs.writeShellScript "link" ''
           ${config.lib.bash.initHomeManagerLib}
 
           newGenFiles="$1"
@@ -220,12 +265,12 @@ in
           done
         '';
 
-        cleanup = pkgs.writeShellScript "cleanup" ''
+        legacyCleanup = pkgs.writeShellScript "cleanup" ''
           ${config.lib.bash.initHomeManagerLib}
 
           # A symbolic link whose target path matches this pattern will be
           # considered part of a Home Manager generation.
-          homeFilePattern="$(readlink -e ${lib.escapeShellArg builtins.storeDir})/*-home-manager-files/*"
+          homeFilePattern="$(readlink -e ${storeDir})/*-home-manager-files/*"
 
           newGenFiles="$1"
           shift 1
@@ -256,38 +301,81 @@ in
             fi
           done
         '';
+
+        # If Putter is not enabled, then generate a fake state file to allow
+        # switching to Putter in the future.
+        putterCompatState =
+          let
+            putter = import ./lib/putter.nix { inherit lib; };
+            manifest = putter.mkPutterCompatState {
+              sourceBaseDirectory = config.home-files;
+              targetBaseDirectory = config.home.homeDirectory;
+              fileEntries = cfg;
+            };
+          in
+          pkgs.writeText "hm-putter-state.json" manifest;
+
+        # This activation script will
+        #
+        # 1. Remove files from the old generation that are not in the new
+        #    generation.
+        #
+        # 2. Symlink files from the new generation into $HOME.
+        #
+        # This order is needed to ensure that we always know which links
+        # belong to which generation. Specifically, if we're moving from
+        # generation A to generation B having sets of home file links FA
+        # and FB, respectively then cleaning before linking produces state
+        # transitions similar to
+        #
+        #      FA   →   FA ∩ FB   →   (FA ∩ FB) ∪ FB = FB
+        #
+        # and a failure during the intermediate state FA ∩ FB will not
+        # result in lost links because this set of links are in both the
+        # source and target generation.
+        legacyLinkGeneration = ''
+          function linkNewGen() {
+            _i "Creating home file links in %s" "$HOME"
+
+            local newGenFiles
+            newGenFiles="$(readlink -e "$newGenPath/home-files")"
+            find "$newGenFiles" \( -type f -or -type l \) \
+              -exec bash ${legacyLink} "$newGenFiles" {} +
+
+            # Copy in the Putter compatible state file. This is to allow a later
+            # switchover to Putter.
+            run install -Dp -m600 $VERBOSE_ARG ${putterCompatState} ${putterStatePath}
+          }
+
+          function cleanOldGen() {
+            if [[ ! -v oldGenPath || ! -e "$oldGenPath/home-files" ]] ; then
+              return
+            fi
+
+            _i "Cleaning up orphan links from %s" "$HOME"
+
+            local newGenFiles oldGenFiles
+            newGenFiles="$(readlink -e "$newGenPath/home-files")"
+            oldGenFiles="$(readlink -e "$oldGenPath/home-files")"
+
+            # Apply the cleanup script on each leaf in the old
+            # generation. The find command below will print the
+            # relative path of the entry.
+            find "$oldGenFiles" '(' -type f -or -type l ')' -printf '%P\0' \
+              | xargs -0 bash ${legacyCleanup} "$newGenFiles"
+          }
+
+          cleanOldGen
+          linkNewGen
+        '';
+
+        putterLinkGeneration = ''
+          ${lib.getExe pkgs.putter} apply $VERBOSE_ARG ''${DRY_RUN:+--dry-run} \
+            --state-file "${putterStatePath}" \
+            ${config.home.internal.filePutterConfig}
+        '';
       in
-      ''
-        function linkNewGen() {
-          _i "Creating home file links in %s" "$HOME"
-
-          local newGenFiles
-          newGenFiles="$(readlink -e "$newGenPath/home-files")"
-          find "$newGenFiles" \( -type f -or -type l \) \
-            -exec bash ${link} "$newGenFiles" {} +
-        }
-
-        function cleanOldGen() {
-          if [[ ! -v oldGenPath || ! -e "$oldGenPath/home-files" ]] ; then
-            return
-          fi
-
-          _i "Cleaning up orphan links from %s" "$HOME"
-
-          local newGenFiles oldGenFiles
-          newGenFiles="$(readlink -e "$newGenPath/home-files")"
-          oldGenFiles="$(readlink -e "$oldGenPath/home-files")"
-
-          # Apply the cleanup script on each leaf in the old
-          # generation. The find command below will print the
-          # relative path of the entry.
-          find "$oldGenFiles" '(' -type f -or -type l ')' -printf '%P\0' \
-            | xargs -0 bash ${cleanup} "$newGenFiles"
-        }
-
-        cleanOldGen
-        linkNewGen
-      ''
+      if config.home.fileActivator == "putter" then putterLinkGeneration else legacyLinkGeneration
     );
 
     home.activation.checkFilesChanged = lib.hm.dag.entryBefore [ "linkGeneration" ] (
@@ -334,6 +422,18 @@ in
       '') (lib.filter (v: v.onChange != "") cfg)
     );
 
+    home.internal.filePutterConfig =
+      let
+        putter = import ./lib/putter.nix { inherit lib; };
+        manifest = putter.mkPutterManifest {
+          inherit putterStatePath;
+          sourceBaseDirectory = config.home-files;
+          targetBaseDirectory = config.home.homeDirectory;
+          fileEntries = cfg;
+        };
+      in
+      pkgs.writeText "hm-putter.json" manifest;
+
     # Symlink directories and files that have the right execute bit.
     # Copy files that need their execute bit changed.
     home-files =
diff --git a/modules/home-environment.nix b/modules/home-environment.nix
index 68c572066..0f44ea7b3 100644
--- a/modules/home-environment.nix
+++ b/modules/home-environment.nix
@@ -912,6 +912,7 @@ in
             --subst-var-by GENERATION_DIR $out
 
           ln -s ${config.home-files} $out/home-files
+          ln -s ${config.home.internal.filePutterConfig} $out/putter.json
           ln -s ${cfg.path} $out/home-path
 
           cp "$extraDependenciesPath" "$out/extra-dependencies"
diff --git a/modules/lib/putter.nix b/modules/lib/putter.nix
new file mode 100644
index 000000000..cc46c6dc3
--- /dev/null
+++ b/modules/lib/putter.nix
@@ -0,0 +1,82 @@
+# Contains some handy functions for generating Putter file manifests.
+
+{ lib }:
+
+let
+
+  inherit (lib)
+    filter
+    hasPrefix
+    optionalAttrs
+    ;
+
+in
+{
+  # Converts a Home Manager style list of file specifications into a Putter
+  # configuration.
+  #
+  # Note, the interface of this function is not considered stable, it may change
+  # as the needs of Home Manager change.
+  mkPutterManifest =
+    {
+      putterStatePath,
+      sourceBaseDirectory,
+      targetBaseDirectory,
+      fileEntries,
+    }:
+    let
+      # Create a Putter entry for the given file.
+      mkEntry =
+        f:
+        {
+          source = "${sourceBaseDirectory}/${f.target}";
+          # source = "${f.source}";
+          target = (if hasPrefix "/" f.target then "" else "${targetBaseDirectory}/") + f.target;
+        }
+        // optionalAttrs f.force {
+          collision.resolution = "force";
+        }
+        // optionalAttrs f.recursive {
+          action.type = "recursive_symlink";
+        };
+
+      putterJson = {
+        version = "1";
+        state = putterStatePath;
+        files = map mkEntry (filter (f: f.enable) fileEntries);
+      };
+
+      putterJsonText = builtins.toJSON putterJson;
+    in
+    putterJsonText;
+
+  # Create a putter state file to allow compatibility between legacy and putter
+  # managed files.
+  #
+  # Note, the interface of this function is not considered stable, it may change
+  # as the needs of Home Manager change.
+  mkPutterCompatState =
+    {
+      sourceBaseDirectory,
+      targetBaseDirectory,
+      fileEntries,
+    }:
+    let
+      mkEntry = f: {
+        name = (if hasPrefix "/" f.target then "" else "${targetBaseDirectory}/") + f.target;
+        value = {
+          source = "${sourceBaseDirectory}/${f.target}";
+          modified = {
+            secs_since_epoch = 0;
+            nanos_since_epoch = 0;
+          };
+        };
+      };
+
+      stateJsonText = builtins.toJSON {
+        version = "1";
+        files = lib.listToAttrs (map mkEntry (filter (f: f.enable) fileEntries));
+      };
+    in
+    stateJsonText;
+}