Transports

The Device Management Kit is offering several transports to communicate with a Ledger device. Depending on the environment and usecase, you can choose the transport that best suits your needs.

Available transports

Transport	Description
Web HID	The WebHID transport uses the Web HID API (usb) to communicate with a Ledger device.
Web BLE	The WebBLE transport uses the Web BLE API (bluetooth) to communicate with a Ledger device.
RN HID	The React Native HID transport uses the react-native (usb) to communicate with a Ledger device.
RN BLE	The React Native BLE transport uses the react-native-ble-plx (bluetooth) to communicate with a Ledger device.
Node HID	The Node HID transport uses the node-hid library (usb) to communicate with a Ledger device.
Speculos	The Speculos transport is used to communicate with the speculos device simulator.

How to use a transport

Transports are injected in the DeviceManagementKitBuilder before building the Device Management Kit instance. This is done by calling the addTransport method on the builder. You can inject the transport in two different ways:

Using the default transport factory provided by the package
Using directly the transport creating your own factory (for custom transports or additional configuration…)


import { DeviceManagementKitBuilder } from "@ledgerhq/device-management-kit";
import { WebHidTransport, webHidTransportFactory } from "@ledgerhq/device-transport-kit-web-hid";
 
// Using the default transport factory
const dmk = new DeviceManagementKitBuilder()
  .addTransport(webHidTransportFactory)
  .build();
 
// Using the transport directly
const dmk = new DeviceManagementKitBuilder()
  .addTransport(({
    deviceModelDataSource: DeviceModelDataSource;
    loggerServiceFactory: (tag: string) => LoggerPublisherService;
    config: DmkConfig;
    apduSenderServiceFactory: ApduSenderServiceFactory;
    apduReceiverServiceFactory: ApduReceiverServiceFactory;
  }) => {
    // Some extra code here to configure the transport
    // Then we return the transport instance
    return new WebHidTransport(
      deviceModelDataSource,
      loggerServiceFactory,
      config,
      apduSenderServiceFactory,
      apduReceiverServiceFactory,
    );
  })
  .build();

How to use the Speculos transport

The Speculos transport is used to communicate with the speculos device simulator. The factory function accepts a speculosUrl parameter that is the url of the speculos server.


const dmk = new DeviceManagementKitBuilder()
  .addTransport(speculosTransportFactory("http://localhost:5000"))
  .build();