Developing Bluetooth Low Energy (BLE) hardware with ESP32, nRF52, Raspberry Pi Pico W, or STM32 requires inspecting the Generic Attribute Profile (GATT) server structure. Having a fast, native Windows GATT explorer makes firmware debugging and IoT telemetry testing significantly easier.
Understanding BLE GATT Architecture
When a central device connects to a BLE peripheral, communication happens through the GATT hierarchy:
- Profiles: Predefined collections of services (e.g. Heart Rate Profile, HID over GATT).
- Services: Logical groupings of data identified by standard 16-bit UUIDs or custom 128-bit UUIDs.
- Characteristics: Individual data endpoints supporting operations such as
Read,Write,Write Without Response,Notify, andIndicate. - Descriptors: Metadata describing characteristic values, such as Client Characteristic Configuration Descriptors (CCCD).
Step-by-Step: Exploring GATT Services with fTool BLE Scanner Pro
Discover Nearby BLE Peripherals
Launch fTool BLE Scanner Pro and start the scan. The app lists all advertising BLE devices, real-time RSSI signal graphs, and parsed manufacturer data.
Connect & Enumerate GATT Hierarchy
Click on your target device to connect. The complete tree of Primary Services, Characteristics, and Descriptors is automatically discovered and organized with standard Bluetooth SIG names.
Execute Read & Write Operations
Select any characteristic to read its current value (displayed in Hex, UTF-8 text, integer, and decimal formats). Send test write payloads directly to debug embedded firmware.
Subscribe to Live Notifications
Toggle Notify / Indicate to receive live streaming sensor streams with timestamped logging and CSV export capabilities.
fTool BLE Scanner Pro for Windows 11 & 10
Professional Bluetooth Low Energy diagnostic suite: complete GATT exploration, Read/Write/Notify testing, raw packet inspection, and telemetry CSV exporting.