<br />

[Firebase
Crashlytics](https://firebase.google.com/docs/crashlytics/unity/get-started)
is a lightweight, realtime crash reporter that makes it easy for you to manage
stability issues in your app. Crashlytics saves you troubleshooting time by
intelligently grouping crashes and highlighting the circumstances that lead up
to them.

This guide describes how to integrate Crashlytics into your Unity project so
that you can log ad response IDs. Later, when you troubleshoot crashes in your
app, you can look up the ad response IDs and use the [Ad Review Center in
AdMob](https://support.google.com/admob/answer/3500252) to find and block the ads.

## Step 1: Add Firebase to your Unity app

Follow the [Firebase Unity integration
guide](https://firebase.google.com/docs/crashlytics/unity/get-started) to
integrate Firebase Crashlytics into Unity.

## Step 2: Log the ad response ID

1. Create a MonoBehaviour script and initialize both AdMob and Firebase SDKs.
   Use the boolean `isCrashlyticsInitialized` to monitor when Crashlytics
   initializes.

   ```c#
   using GoogleMobileAds.Api;
   using Fabric.Crashlytics;
   ...
   public class GameObjectScript : MonoBehaviour
   {
       bool isCrashlyticsInitialized = false;
       public void Start()
       {
           ....
           // Initialize Google Mobile Ads Unity Plugin.
           MobileAds.Initialize(initStatus => { });
           ....
           // Initialize Firebase
           Firebase.FirebaseApp.CheckAndFixDependenciesAsync().ContinueWith(task => {
               Firebase.DependencyStatus dependencyStatus = task.Result;
               if (dependencyStatus == Firebase.DependencyStatus.Available)
               {
                   Firebase.FirebaseApp app = Firebase.FirebaseApp.DefaultInstance;
                   isCrashlyticsInitialized = true;
               }
               else
               {
                   UnityEngine.Debug.LogError(System.String.Format(
                     "Could not resolve all Firebase dependencies: {0}",dependencyStatus));
                   // Firebase Unity SDK is not safe to use here.
               }
           }
       }
   }
   ```
2. Request a banner ad.

   ```c#
   using GoogleMobileAds.Api;
   using Fabric.Crashlytics;
   ...
   public class GameObjectScript : MonoBehaviour
   {

       public void Start()
       {
           ...
           // Initialize Google Mobile Ads Unity Plugin.
           MobileAds.Initialize(initStatus => { });

           // Initialize Firebase.
           Firebase.FirebaseApp.CheckAndFixDependenciesAsync().ContinueWith(task => {
               Firebase.DependencyStatus dependencyStatus = task.Result;
               if (dependencyStatus == Firebase.DependencyStatus.Available)
               {
                   // Create and hold a reference to your FirebaseApp,
                   // where app is a Firebase.FirebaseApp property of your
                   // application class.
                   // Crashlytics will use the DefaultInstance, as well;
                   // this ensures that Crashlytics is initialized.
                   Firebase.FirebaseApp app = Firebase.FirebaseApp.DefaultInstance;
                   isCrashlyticsInitialized = true;
               }
               else
               {
                   UnityEngine.Debug.LogError(System.String.Format(
                       "Could not resolve all Firebase dependencies: {0}",dependencyStatus));
                   // Firebase Unity SDK is not safe to use here.
               }
           });

           // Request Banner View.
   this.RequestBanner();
   ...
   }
   public void RequestBanner()
   {
   #if UNITY_ANDROID
   string adUnitId = "ca-app-pub-3940256099942544/6300978111";
   #elif UNITY_IPHONE
   string adUnitId = "ca-app-pub-1220882738324941/1255739139";
   #else
   string adUnitId = "unexpected_platform";
   #endif
   // Create a 320x50 banner at the top of the screen.
   this.bannerView = new BannerView(adUnitId, AdSize.Banner, AdPosition.Bottom);
   AdRequest request = new AdRequest();
   this.bannerView.LoadAd(request);
   // Called when an ad request has successfully loaded.
   this.bannerView.OnAdLoaded += this.HandleOnAdLoaded;
   }
   }
   ```
3. Get the `ResponseInfo` object `OnAdLoaded` and log the response ID to
   Crashlytics.

   ```c#
   public void HandleOnAdLoaded(object sender, EventArgs args)
   {
       ResponseInfo responseInfo = this.bannerView.GetResponseInfo();
       if (responseInfo != null)
       {
           String adResponseId = responseInfo.GetResponseId();
           // Log to Crashlytics.
           if (isCrashlyticsInitialized)
           {
               Crashlytics.SetCustomKey("banner_ad_response_id", adResponseId);
           }
       }
   }
   ```

That's it! You can now see the most recent `banner_ad_response_id` in the key
section of crash sessions on your Crashlytics dashboard. Note that some keys may
take up to four hours to become visible on your dashboard.

![response id](https://developers.google.com/static/admob/images/response-id.png)