Bluetooth Low Energy: GATT, Permissions, and Background Connections in React Native

Bluetooth Low Energy powers wearables, sensors, and retail beacons with lower duty cycles than classic Bluetooth—yet exposes intricate GATT service discovery, characteristic subscriptions, and connection parameter negotiation. React Native relies on native modules wrapping CoreBluetooth and Android BluetoothGatt.

Permissions and OS versions

Android 12 introduced granular BLUETOOTH_SCAN and BLUETOOTH_CONNECT runtime permissions—update manifests and user education flows. iOS requires usage strings for Bluetooth access on recent versions when scanning in background contexts.

Scanning and throttling

Android may throttle frequent scans to protect battery—batch discovery phases and cache known peripheral identifiers. Respect manufacturer pairing requirements; some devices need bonding before reliable writes.

Throughput and MTU

Negotiate larger ATT MTU when firmware supports it to reduce fragmentation for bulk transfers. Implement application-level framing with checksums—BLE is lossy at the application layer if firmware misbehaves.

Background execution

iOS background BLE modes extend app lifetime cautiously—misuse risks review rejection. Android foreground services may be necessary for sustained connections—display mandatory notifications per policy.

Testing

Hardware variability dwarfs pure software QA—maintain a device farm of representative peripherals and firmware versions. Log RSSI and disconnect reasons for field diagnostics.

Conclusion

BLE features are partnership projects with firmware teams—align on state machines, OTA update channels, and failure analytics before mass deployment.