ByteProbe: A BLE Inspector for Android Developers

Bluetooth Low Energy development involves a lot of invisible state: GATT services, characteristics, descriptors, advertising packets. When something isn't working, you need a way to see what the device is actually doing rather than what your code thinks it's doing. ByteProbe is a BLE inspector that gives you exactly that visibility.

What BLE Actually Is

Bluetooth Low Energy is a wireless protocol designed for devices that transmit small amounts of data infrequently — fitness trackers, heart rate monitors, sensors, smart locks, industrial sensors, and similar IoT devices. The "low energy" part means a well-designed BLE device can run on a coin cell battery for months or years.

BLE uses a profile system called GATT (Generic Attribute Profile). A GATT server (the BLE peripheral) exposes a hierarchy of services → characteristics → descriptors. Services group related functionality, characteristics hold the actual data (readable, writable, or notifiable), and descriptors contain metadata about characteristics.

What ByteProbe Shows You

• Device scanner — lists nearby BLE devices with RSSI signal strength, device name, and advertising data. RSSI updates in real time so you can see signal changes as you move.
• GATT browser — connect to any device and browse its full service tree. Services are identified by UUID and resolved to human-readable names for standard profiles (Battery Service, Device Information, Heart Rate, etc.)
• Characteristic reader — read the current value of any readable characteristic. Values are displayed in hex, decimal, and decoded ASCII so you can see the raw bytes and any text interpretation.
• Notifications — subscribe to notifiable characteristics and watch live value updates as the device broadcasts them. Useful for sensor data and real-time monitoring.
• Write — write values to writable characteristics for testing commands and configuration
• Traffic log — a timestamped log of all GATT operations in the session

Typical Development Workflow

When you're building an Android app that talks to a BLE peripheral, ByteProbe lets you verify the device's behavior before you write any code. Connect to the device, find the service and characteristic your app will use, confirm the UUID, and see what format the data arrives in. This saves significant debugging time compared to instrumenting your app code and chasing logs.

It's also useful for reverse engineering undocumented BLE devices. Many consumer BLE devices don't publish their GATT profiles. ByteProbe lets you explore the services and characteristics and observe what happens when you trigger different device states.

Standard UUIDs vs Vendor UUIDs

Bluetooth SIG defines standard 16-bit UUIDs for common profiles — 0x180F is Battery Service, 0x2A19 is Battery Level. ByteProbe resolves these automatically. Custom vendor services use 128-bit UUIDs in a vendor-specific format, which ByteProbe displays as-is.

Download ByteProbe from Google Play — free, works with any BLE device.