React native Bluetooth

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Sections in this article

Install the package

yarn add @ledgerhq/react-native-hw-transport-ble



In some cases, the link with the phone may break, it is in this case recommended to users to go to their phone settings and manually Forget the Nano X. There is at the moment no other way: there is no programmatic way to unpair a bonded device but you can however have a button that opens the Bluetooth section of the phone’s settings.

Minimal getting started

@ledgerhq/react-native-hw-transport-ble works like any of our @ledgerhq/hw-transport libraries.

The difference here is that the listen() is costy and you likely don’t want to always scan for devices, you would better save a selected device as “known” to suggest it to user later.

Important: you will also have to deal with specifics of Bluetooth BLE, for instance, you need to request the LOCATION permission on Android!

Here is a gist of the most important parts required.

Check for Bluetooth state

import TransportBLE from "@ledgerhq/react-native-hw-transport-ble";

const subscription = TransportBLE.observeState({
  next: e => syncWithUI(e.available),
  complete: () => {},
  error: () => {}

when Bluetooth is available we can continue to…

Scan for devices

const subscription = TransportBLE.listen({
  complete: () => {
    this.setState({ refreshing: false });
  next: e => {
    if (e.type === "add") {
      const device = e.descriptor;
  error: error => {
    this.setState({ error, refreshing: false });

// NB we also recommend the use of RxJS, you can just wrap it like so:
// Observable.create(TransportBLE.listen).subscribe({ ... })
// In the future of ledgerjs, we might directly returns Observable.

This is the basic idea, obviously you need to call this code in your logic and implement addDeviceToTheUI(device).

In that device object, you can typically use two fields:

  • a unique identifier of the device that can later be given to
  • the name of the device (e.g. NanoX A4F5)

With this device we can now…

Connect to known device

const transport = await;
// OR
const transport = await; // deviceId can come from persisted state. It's unique per device

and now we can just use the transport like any other Ledger transport!


Extends Transport

react-native bluetooth BLE implementation


  • device Device
  • writeCharacteristic Characteristic
  • notifyObservable Observable<Buffer>
  • deviceModel DeviceModel


import BluetoothTransport from "@ledgerhq/react-native-hw-transport-ble";


communicate with a BLE transport


Returns Promise<Buffer>


Returns Promise<boolean>



  • level any


TODO could add this concept in all transports observe event with { available: bool, string } // available is generic, type is specific an event is emit once and then listened


  • observer any


Scan for bluetooth Ledger devices


  • observer any


Open a BLE transport


  • deviceOrId any


Globally disconnect a BLE device by its ID


  • id any

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