# 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):**

```kotlin
import com.ledger.devicemanagement.DeviceManagementKitApi
import com.ledger.devicemanagement.deviceManagementKit

val dmk: DeviceManagementKitApi = deviceManagementKit {
    context = applicationContext
    enableLog = true
}
```

**iOS (Swift):**

```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:

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

> **Warning:** Both `discoveryTimeout` and `connectionTimeout` must be strictly greater than
> zero, otherwise the builder will throw an exception.

## Step 3: Keep it as a singleton

> **Caution:** 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.

```kotlin
// 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:

```kotlin
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