CoderTools

Web Bluetooth Debugger

Scan BLE devices, monitor RSSI signal strength, and explore GATT services

How to Use

1

Click 'Scan for BLE Devices'

This will open your browser's Bluetooth device picker dialog. Your browser will search for nearby BLE devices and display them in a list.

2

Select a Device

Choose the BLE device you want to debug from the browser's picker. The device will then connect to this tool.

3

Explore GATT Services

After connecting, click 'Connect GATT' to discover all services and characteristics exposed by the device. You can read, write, and subscribe to notifications.

4

Monitor Signal Strength

Use the RSSI monitor to track the Bluetooth signal strength in real-time. This helps identify connectivity issues or optimal device placement.

Features

BLE Device Scanning

Scan for nearby Bluetooth Low Energy devices using the Web Bluetooth API. Connect to any compatible BLE device directly from your browser.

RSSI Signal Monitoring

Monitor real-time signal strength (RSSI) with a visual graph. Track signal quality over time to diagnose connectivity issues.

GATT Service Explorer

Discover and explore all GATT services and characteristics. View service UUIDs, characteristic properties, and descriptors in a tree structure.

Read/Write Values

Read characteristic values in Hex, Text, or Decimal format. Write values to writable characteristics for device control and testing.

Notification Subscription

Subscribe to characteristics with Notify or Indicate properties. View a timestamped log of all incoming notifications.

Browser Compatibility

Web Bluetooth API support varies by browser and operating system:

  • Chrome 56+ — Full support on Windows, macOS, Linux, Android, ChromeOS
  • Edge 79+ — Full support on Windows, macOS
  • Opera 43+ — Full support
  • Firefox — Not supported (no Web Bluetooth implementation)
  • Safari — Not supported (experimental flag available but limited)

Browser Limitations

Frequently Asked Questions

Why doesn't my device appear in the scan results?

Ensure your device is powered on and in advertising mode. Some devices stop advertising after pairing with another device. Also check that Bluetooth is enabled on your computer and the device is within range.

Can I see the actual MAC address of the BLE device?

No, browsers intentionally hide real MAC addresses for privacy reasons. The Device ID shown is a unique identifier generated by your browser for this origin. It's consistent for the same device on the same website but different across websites.

Why is RSSI monitoring showing 'Not Supported'?

RSSI monitoring via watchAdvertisements() requires Chrome 85+ or Edge 85+. Some operating systems (like iOS) do not support this feature even in supported browsers. On older browsers, RSSI is only available during the initial scan.

Why can't I write to a characteristic?

Check if the characteristic has the 'Write' or 'Write Without Response' property. Some characteristics are read-only. Also ensure the value format is correct — hex values should be space-separated bytes like '01 02 03'.

Is my data sent to any server?

No. This tool runs entirely in your browser using the Web Bluetooth API. All communication happens directly between your browser and the BLE device. No data is transmitted to our servers.

Why does the connection keep dropping?

BLE connections can be unstable due to: 1) Distance/obstacles between device and computer, 2) Interference from other wireless devices, 3) Device firmware issues, 4) Low battery on the BLE device. Try moving closer or removing obstacles.

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