# Initialize the SDK in Unity

> Initialize the Unity Ads SDK with your Game ID to enable monetization and access Unity Ads public APIs in your Unity project.

To initialize the SDK, you must reference your project's Game ID for the appropriate platform. You can locate the Game ID from the [Unity Ads Monetization dashboard](https://cloud.unity.com/monetization) by selecting the **Monetization** suite, navigating to your current project, then **Settings** in the secondary navigation bar, and scrolling to the **Game IDs** section.

> **Note:**
>
> Starting April 1, 2026, apps that monetize with Unity Ads through direct integration through the Advertisement Legacy Package might see reduced ad performance. To avoid reduction in performance, switch to integrating Unity Ads as a bidder.
>
> The Unity Ads network will continue to support and provide fill for all apps using direct integration. However, to maximize revenue and performance, the recommended best practice is to [install the Ads Mediation package for LevelPlay](/grow/levelplay/sdk/unity/package-integration.md.md), Unity's ad mediation platform.

In your game script header, include the `UnityEngine.Advertisements` namespace. Initialize the SDK early in the game's run-time life cycle, preferably at launch, using the `Initialize` function. In SDK versions 3.7.0 and later, you can use `IUnityAdsInitializationListener` callbacks to receive a notification when initialization is complete, or receive the details when an error occurs.

## SDK initialization example

1. **C#**

   ```cs
   using UnityEngine;
   using UnityEngine.Advertisements;

   public class AdsInitializer : MonoBehaviour, IUnityAdsInitializationListener
   {
     [SerializeField] string _androidGameId;
     [SerializeField] string _iOSGameId;
     [SerializeField] bool _testMode = true;
     private string _gameId;

     void Awake()
     {
       InitializeAds();
     }

     public void InitializeAds()
     {
       #if UNITY_IOS
       _gameId = _iOSGameId;
       #elif UNITY_ANDROID
       _gameId = _androidGameId;
       #elif UNITY_EDITOR
       _gameId = _androidGameId; //Only for testing the functionality in the Editor
       #endif

       if (!Advertisement.isInitialized && Advertisement.isSupported)
       {
         Advertisement.Initialize(_gameId, _testMode, this);
       }
     }

     public void OnInitializationComplete()
     {
       Debug.Log("Unity Ads initialization complete.");
     }

     public void OnInitializationFailed(UnityAdsInitializationError error, string message)
     {
       Debug.Log($"Unity Ads Initialization Failed: {error.ToString()} - {message}");
     }
   }
   ```

**Next steps**: To continue your integration, refer to the [Implement interstitial ads in Unity](/monetization/sdk-integration/unity-sdk/interstitial-ads.md) documentation.