MultitouchExtension integration

Karabiner-MultitouchExtension allows you to change keys only when the finger is on the trackpad.

You can use variable_if or variable_unless to determine either the finger is on trackpad.


The following json changes k key to up_arrow when the finger is on the trackpad.

    "type": "basic",
    "from": {
        "key_code": "k",
        "modifiers": {
            "optional": ["any"]
    "to": [
            "key_code": "up_arrow"
    "conditions": [
            "type": "variable_unless",
            "name": "multitouch_extension_finger_count_total",
            "value": 0


Karabiner-MultitouchExtension changes the following variables when the finger count on the trackpad is changed.

Name Value
multitouch_extension_finger_count_total Total count of fingers on the trackpad
multitouch_extension_finger_count_upper_half_area Count of fingers on the upper half of trackpad
multitouch_extension_finger_count_lower_half_area Count of fingers on the lower half of trackpad
multitouch_extension_finger_count_left_half_area Count of fingers on the left half of trackpad
multitouch_extension_finger_count_right_half_area Count of fingers on the right half of trackpad

You can confirm the variables state on Karabiner-EventViewer > Variables.