diff --git a/keymapper/gtk/window.py b/keymapper/gtk/window.py
index cb573d5e..45e63c33 100755
--- a/keymapper/gtk/window.py
+++ b/keymapper/gtk/window.py
@@ -277,8 +277,8 @@ class Window:
 
         try:
             # new_preset = create_preset(self.selected_device)
-            # TODO create a preset file, tell custom_mapping to do so
-            #  or something
+            # TODO create a preset file, tell custom_mapping to clear itself
+            #  and dump itself into a new file
             new_preset = 'new_preset'
             self.get('preset_selection').append(new_preset, new_preset)
             self.get('preset_selection').set_active_id(new_preset)
@@ -339,7 +339,7 @@ class Window:
         key_list.remove(single_key_mapping)
 
     def save_config(self):
-        """Write changes to disk"""
+        """Write changes to disk."""
         if self.selected_device is None or self.selected_preset is None:
             return
 
@@ -349,7 +349,7 @@ class Window:
             self.selected_preset
         )
 
-        # TODO tell the mapping to dump itself as JSON somewhere
+        custom_mapping.save(self.selected_device, self.selected_preset)
 
         custom_mapping.changed = False
         self.unhighlight_all_rows()
diff --git a/keymapper/mapping.py b/keymapper/mapping.py
index abbfb8d5..1bbd6914 100644
--- a/keymapper/mapping.py
+++ b/keymapper/mapping.py
@@ -22,6 +22,8 @@
 """Contains and manages mappings."""
 
 
+import json
+
 from keymapper.logger import logger
 
 
@@ -96,6 +98,14 @@ class Mapping:
         self._mapping = {}
         self.changed = True
 
+    def load(self, device, preset):
+        """Load a dumped JSON from home to overwrite the mappings."""
+        # TODO
+
+    def save(self, device, preset):
+        """Dump as JSON into home."""
+        # TODO
+
     def get_keycode(self, character):
         """Get the keycode for that character."""
         # TODO prepare this with .lower() instead to make it faster
@@ -118,12 +128,6 @@ class Mapping:
         """
         return self._mapping.get(keycode)
 
-    def has(self, keycode):
-        """Check if this keycode is going to be a line in the symbols file.
-        TODO no symbols files anymore ^
-        """
-        return self._mapping.get(keycode) is not None
-
 
 # one mapping object for the whole application that holds all
 # customizations