Bluetooth Battery Monitor HTTP/JSON API

Starting version 2.8.0, Bluetooth Battery Monitor supports an API so that 3rd party developers can create their own user interface. This page explains how to enable it and how to use it.

Enabling the API

This feature is not enabled by default and needs to be enabled using the following Windows registry settings under the HKEY_CURRENT_USER\Software\Luculent Systems\Bluetooth Battery Monitor\ApiServer registry key. Please note that this registry key may not exist by default.

Name Type Default Note
port DWORD N/A

This value must be added to enable the HTTP server for the API support.

The HTTP server will listen to the TCP port number specified by this setting.

ip String ""

This optional value specifies which IP address the HTTP server will be bound to.

If you are using the API only from the local computer, use "". If you are using the API over the network, please enter the IP address of the network interface.

These registry settings are checked at the Bluetooth Battery Monitor's startup. So, you need to restart the Bluetooth Battery Monitor (BattMonUI.exe) after changing these registry settings.

Using the API

Current API implements only one endpoint GET /devices, which returns the JSON object that contains the following attributes.

Name Type Note
version string Version number of the running Bluetooth Battery Monitor. (e.g. "")
devices array An array of the device object which contains the information about each Bluetooth device.

device object contains the following attributes.

Name Type Note
name string Name of the device as it appears in the user interface.
icon string Path of the device icon resource in the form of "file-path,-resurce id".
level integer/null Battery level in percent (0 .. 100).
connected bool Current device connection status.
secs_since_update integer/null The time since this device reported its battery level.
extra string/null

Extra information about the device (if any).

For example, for AirPods, this attribute returns "L:50 R:40 C:60" to show the left, right, and case battery level.

Please note that the type of information and its format can change without notice. So, plesase do not try to parse this message.

Example JSON response

  "version": "",
  "devices": [
      "connected": false,
      "extra": null,
      "icon": "C:\\Windows\\System32\\DDORes.dll,-3022",
      "level": null,
      "name": "iPhone",
      "secs_since_update": null
      "connected": true,
      "extra": null,
      "icon": "C:\\Windows\\System32\\DDORes.dll,-3073",
      "level": 100,
      "name": "ThinkPad Compact Bluetooth Keyboard with TrackPoint",
      "secs_since_update": 18234


Quick Example

  1. Setup registry for local access.
  2. Open a command prompt window and enter the following command:
    reg add "HKCU\Software\Luculent Systems\Bluetooth Battery Monitor\ApiServer" /f /reg:64 /v port /t REG_DWORD /d 9876
    This will set up the HTTP server at IP address port 9876.

  3. Restart Bluetooth Battery Monitor (BattMonUI.exe).
  4. Try the API.
  5. Enter the following command into the command prompt window: curl
    You should see the JSON response.


Contacting Us

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