<p><i>BLEtoMQTT</i> is an Android foreground service to provide a bidirectional bridge between BLE devices and an MQTT broker. A <code>setup.json</code> file defines MQTT parameters and BLE MAC addresses to scan for.</p><p>For each BLE device detected BLEtoMQTT will discover all exposed services and characteristics creating MQTT topics for each. Those characteristics which are writeable will automatically be 'subscribed' from the MQTT broker.</p><p>The author uses this application to connect remote custom ESP32 devices to his Home Assistant server via a Zerotier VPN. The app's source repository contains an example <code>setup.json</code> and a prebuilt apk used to monitor/control a boat on a mooring or at anchor. It also has more detailed setup instructions.</p>