Initializing and Configuring the DMK

In this guide, you’ll learn how to initialize and configure the Device Management Kit (DMK) for your application. By the end, you’ll have a working DMK instance ready to interface with Ledger devices.

What you’ll learn

How to initialize the DMK using the Kotlin DSL
What configuration options are available
How to maintain the DMK instance as a singleton

Step 1: Create the DMK instance

Use the deviceManagementKit builder DSL to obtain an instance of DeviceManagementKitApi. This should be done once in your application lifecycle.

Android (Kotlin):


import com.ledger.devicemanagement.DeviceManagementKitApi
import com.ledger.devicemanagement.deviceManagementKit
 
val dmk: DeviceManagementKitApi = deviceManagementKit {
    context = applicationContext
    enableLog = true
}

iOS (Swift):


import LedgerDMK
 
let dmk = DeviceManagementKit.build()

Step 2: Configuration options

The builder DSL exposes the following parameters:

Parameter	Type	Default	Description
`context`	`Any?`	`null`	Android application context — required on Android
`discoveryTimeout`	`Duration`	`1.minutes`	How long the SDK scans for nearby devices before stopping
`connectionTimeout`	`Duration`	`15.seconds`	How long the SDK waits for a device connection before failing
`enableLog`	`Boolean`	`false`	Enable SDK-wide logging
`enableFake`	`Boolean`	`false`	Use fake device implementations — useful for testing

Example with all options:


val dmk: DeviceManagementKitApi = deviceManagementKit {
    context = applicationContext
    discoveryTimeout = 2.minutes
    connectionTimeout = 30.seconds
    enableLog = true
    enableFake = false
}

⚠️

Both discoveryTimeout and connectionTimeout must be strictly greater than zero, otherwise the builder will throw an exception.

Step 3: Keep it as a singleton

🚨

The DMK can only be initialized once per application runtime. Attempting to create a second instance will throw an exception. Always keep a single reference and share it across your application.


// Application.kt
class MyApplication : Application() {
    lateinit var dmk: DeviceManagementKitApi
 
    override fun onCreate() {
        super.onCreate()
        dmk = deviceManagementKit {
            context = applicationContext
            enableLog = BuildConfig.DEBUG
        }
    }
}

Step 4: Release resources

Call destroy() when your application closes to release all resources held by the DMK:


dmk.destroy()

What you’ve learned

How to initialize the DMK with the deviceManagementKit { } Kotlin DSL
The available configuration parameters and their defaults
Why the DMK must be treated as a singleton
How to properly release resources on shutdown