This guide is intended for ad networks looking to build a bidding adapter in order to participate in real-time bidding (RTB) within Google mediation. If you are a publisher, see the publisher mediation instructions.
A bidding adapter is the client-side part of the integration. The adapter enables your ad network SDK to communicate with the Google Mobile Ads SDK to load ads served by your bidder.
For bidding to work correctly your adapter will need to handle initialization, collecting signals, loading ads, and relaying ad lifecycle events. In this guide we will walk you through how your adapter should be implemented to handle these operations.
Workflow of a bidding adapter
Initialization
A detailed flow of the entire request-response-rendering lifecycle of an adapter is shown below:
The adapter is responsible for the following portions of the workflow:
Steps 4-7: Initialize your adapter and call back the Google Mobile Ads SDK once initialization completes.
Steps 10-13: Collect signals from your ad network SDK to be sent to your bidder to participate in an RTB request, and forward them to the Google Mobile Ads SDK.
Steps 18-21: Should your bidder return the winning bid, load the ad according to the response from your bidder. Once loaded, notify the Google Mobile Ads SDK that the ad was loaded.
Step 23 and later: While your ad is displaying, notify the Google Mobile Ads SDK of impression and click events, as well as the other ad events that occur during the presentation lifecycle of your ad.
Implementing the bidding adapter
To create a bidding adapter for the Google Mobile Ads SDK, you must
extend the RtbAdapter
abstract class. The following sections
explain each abstract method in RtbAdapter
.
getSDKVersionInfo()
Here you should return your SDK's version. This version is passed to your bidder as part of the OpenRTB request.
This method requires you to return a VersionInfo
. The example below shows how
you might convert your SDK's string version into a VersionInfo.
@Override
public VersionInfo getSDKVersionInfo() {
// Get your SDK's version as a string. E.g. "1.2.3"
// String versionString = YourSdk.getVersion();
String splits[] = versionString.split("\\.");
if (splits.length >= 3) {
int major = Integer.parseInt(splits[0]);
int minor = Integer.parseInt(splits[1]);
int micro = Integer.parseInt(splits[2]);
return new VersionInfo(major, minor, micro);
}
String logMessage = String.format("Unexpected SDK version format: %s." +
"Returning 0.0.0 for SDK version.", sdkVersion);
Log.w(TAG, logMessage);
return new VersionInfo(0, 0, 0);
}
getVersionInfo()
Here you should return your adapter's version. This version is passed to your bidder as part of the OpenRTB request.
Google's open source and versioned
adapters
use a 4-digit adapter version scheme, but the VersionInfo
only allows for 3
digits. To work around this, it is recommended to combine the last two digits
into the patch version, as shown below.
@Override
public VersionInfo getVersionInfo() {
// Get your adapters's version as a string. E.g. "1.2.3.0"
String versionString = BuildConfig.VERSION_NAME;
String splits[] = versionString.split("\\.");
if (splits.length >= 4) {
int major = Integer.parseInt(splits[0]);
int minor = Integer.parseInt(splits[1]);
int micro = Integer.parseInt(splits[2]) * 100 + Integer.parseInt(splits[3]);
return new VersionInfo(major, minor, micro);
}
String logMessage = String.format("Unexpected adapter version format: %s." +
"Returning 0.0.0 for adapter version.", versionString);
Log.w(TAG, logMessage);
return new VersionInfo(0, 0, 0);
}
initialize()
Timeout: 30 seconds
The initialize()
method is the first method called in your adapter. It is
called only once per session. This method provides you with a list of
MediationConfiguration
objects that represent the full list of
placements in this app that are configured for your ad network; You can loop
through this list to parse the credentials for each placement,
and pass relevant data to your SDK for initialization.
Once your SDK is initialized and is ready to receive ad requests, invoke the
onInitializationSucceeded()
method of the InitializationCompleteCallback
.
This callback is forwarded to the app publishers so that they can know they
can start loading ads.
@Override
public void initialize(Context context,
InitializationCompleteCallback initializationCompleteCallback,
List<MediationConfiguration> mediationConfigurations) {
// Initialize your ad network's SDK.
...
// Invoke the InitializationCompleteCallback once initialization completes.
initializationCompleteCallback.onInitializationSucceeded();
}
collectSignals()
Timeout: 1 second
Each time the publisher requests an ad, a new instance of your RtbAdapter
is
created and the collectSignals()
method is called. This instance of
RtbAdapter
will be used for the duration of the ad request, response, and
rendering lifecycle for that ad. The collectSignals()
method enables your
adapter to provide signals from the device to be sent to your bidder in an
OpenRTB request.
collectSignals()
is called on a background thread.
The Google Mobile Ads SDK simultaneously asks for signals from all adapters
participating in bidding. Please be respectful and limit calls to the UI thread
during this time. Any heavy work that your adapter or SDK needs to do to collect
signals should be done in the initialize()
method and cached.
Once you have your signals ready, call the onSuccess()
callback with your
encoded signals.
Here's an example implementation:
@Override
public void collectSignals(RtbSignalData rtbSignalData,
SignalCallbacks signalCallbacks) {
String signals = YourSdk.getSignals();
signalCallbacks.onSuccess(signals);
}
If your adapter fails to collect signals, call signalCallbacks.onFailure()
with a string explaining the error that occurred.
Implement ad loading methods
Timeout: 10 seconds
If your bidder returns the winning bid, the Google Mobile Ads SDK calls your adapter to load the winning ad, passing you any data that your bidder returned that your SDK needs to load that ad.
The exact load method that is called depends on the ad format this request is for:
Ad Format | Load method |
---|---|
Banner | loadBannerAd()
|
Interstitial | loadInterstitialAd()
|
Rewarded | loadRewardedAd()
|
Implement these methods for the ad formats your adapter supports.
The load method is called on the UI thread, on the same instance of the adapter from which you provided signals. This method provides you the following parameters:
A
MediationAdConfiguration
, which contains parameters your SDK needs to load the ad for the winning bid, such as the bid response and any credentials the publisher configured in the AdMob UI.A
MediationAdLoadCallback
object used to notify the Google Mobile Ads SDK when the loading succeeds or fails.
Once your SDK loads the ad, call mediationAdLoadCallback.onSuccess()
. In the
event ad loading fails, call mediationAdLoadCallback.onFailure()
with a
string explaining the error that occurred.
The mediationAdLoadCallback.onSuccess()
method requires that you pass in an
object that confirms to one of the "Ad" interfaces defined by the Google Mobile
Ads SDK. These ad interfaces ask you to provide some information about the ad.
MediationAdConfiguration
also has a getWatermark()
method to return a base64-encoded string representing a PNG image. This image
should be tiled in a transparent overlay on your ads.
Reach out to Google for additional guidance on how to render the watermark.
It contains metadata about the ad being shown for use by publishers to determine
the source of ads shown.
For banners, you'll be asked to provide the banner view. For interstitial and
rewarded ads, you'll be asked to implement a show()
method to show the ad at
a later point in time. As a best practice, we recommend making your class that
does the ad loading also be responsible for implementing these ad methods.
The following is a sample implementation of loadBannerAd()
. Keep in mind
that your adapter's implementation will look different, as your adapter
integrates against a different SDK.
public final class SampleRtbAdapter extends RtbAdapter {
...
@Override
public void loadBannerAd(
MediationBannerAdConfiguration adConfiguration,
MediationAdLoadCallback<MediationBannerAd, MediationBannerAdCallback> callback) {
SampleBannerRenderer bannerRenderer =
new SampleBannerRenderer(adConfiguration, callback);
bannerRenderer.render();
}
}
// Renders a banner ad, and forwards callbacks to the Google Mobile Ads SDK.
public class SampleBannerRenderer implements MediationBannerAd {
private MediationBannerAdConfiguration adConfiguration;
private final MediationAdLoadCallback<MediationBannerAd, MediationBannerAdCallback> adLoadCallback;
private AdView adView;
private MediationBannerAdCallback callback;
public SampleRtbBannerRenderer(
MediationBannerAdConfiguration adConfiguration,
MediationAdLoadCallback<MediationBannerAd, MediationBannerAdCallback> adLoadCallback) {
this.adConfiguration = adConfiguration;
this.adLoadCallback = adLoadCallback;
}
public void render() {
adView = new AdView(adConfiguration.getContext());
adView.setAdSize(adConfiguration.getAdSize());
// serverParameters are the parameters entered in the AdMob UI for your network.
adView.setAdUnitId(adConfiguration.getServerParameters().getString("adUnitId"));
// Map the callbacks from your SDK to Google's SDK.
adView.setAdListener(new AdListener() {
// See the next step for more information on callback mapping.
// ...
});
// Get the bid response and watermark from the ad configuration and
// pass the relevant information to your SDK.
String ad = adConfiguration.getBidResponse();
String watermark = adConfiguration.getWatermark();
Bundle extras = new Bundle();
extras.putString("bid", ad);
extras.putString("watermark", watermark);
AdRequest request = new AdRequest.Builder()
.addNetworkExtrasBundle(AdMobAdapter.class, extras)
.build();
adView.loadAd(request);
}
// MediationBannerAd implementation
@NonNull
@Override
public View getView() {
return adView;
}
}
Relay ad presentation lifecycle events
The final responsibility of the adapter is to notify the Google Mobile Ads SDK of any presentation lifecycle events, so that they can be forwarded to the publisher. The publisher expects these callbacks at specific times no matter which ad network serves the ad, so it's important that as many of these callbacks are invoked as possible, and at the right time, so that the Google Mobile Ads SDK can forward them to the publisher.
Adapters should invoke the following events when applicable:
Common to all formats | |
---|---|
Method | When to call |
reportAdClicked()
|
The ad was clicked. |
reportAdImpression()
|
The ad rendered an impression. |
onAdOpened()
|
The ad presented a full screen view. |
onAdClosed()
|
The ad's full screen view has been closed. |
onAdLeftApplication()
|
The ad caused the user to leave the application. |
Rewarded ads | |
onRewarded()
|
The user is granted a reward. |
Video callbacks (rewarded and native ads) | |
onVideoStarted()
|
The ad's video started. |
onVideoCompleted()
|
The ad's video completed. |
The adapter gets a MediationAdLoadCallback<MediationAdT, MediationAdCallbackT>
object back upon calling mediationAdLoadCallback.onSuccess()
. Adapters are
expected to hold onto this object and use it to invoke presentation events
that occur on your ad.
Typically, most of these events are driven by your ad network's SDK. The adapter's role is simply to map the callbacks from your ad network SDK to the Google Mobile Ads SDK.
The following example demonstrates how you would forward callbacks from your SDK's ad listener to the Google Mobile Ads SDK:
adView.setAdListener(new AdListener() {
public void onAdLoaded() {
callback = adLoadCallback.onSuccess(SampleBannerRenderer.this);
}
public void onAdImpression() {
if (callback != null) {
callback.reportAdImpression();
}
}
public void onAdFailedToLoad(LoadAdError adError) {
adLoadCallback.onFailure("Error: " + adError.toString());
}
public void onAdClosed() {
if (callback != null) {
callback.onAdClosed();
}
}
public void onAdOpened() {
if (callback != null) {
callback.onAdOpened();
callback.reportAdClicked();
}
}
public void onAdLeftApplication() {
if (callback != null) {
callback.onAdLeftApplication();
}
}
});
Required assets for native ad impression tracking
The Google Mobile Ads SDK records an impression for a native ad when 1 px of the ad is visible. If your ad network SDK requires specific assets to be displayed in order to render a valid impression, your bidder can indicate these required native assets in the bid response. The Google Mobile Ads SDK then validates that your required native assets are displayed prior to recording an impression.
See the native required assets documentation for more information on how to specify additional required assets in the bid response.
Show ad errors
For full screen formats, such as interstitial and rewarded ads, in the success
load callback you will provide an implementation of
MediationInterstitialAd
or MediationRewardedAd
so that the Google Mobile Ads SDK can ask your adapter to show the ad.
The Google Mobile Ads SDK expects that if an adapter successfully loaded an ad, the ad is ready to show when the publisher asks to show it. This means that every show call should result in an impression.
However, there may be corner cases where you're unable to show an ad. If you
can't show the ad, call the
onAdFailedToShow()
callback to cancel the impression.
The table below shows how presentation callbacks affect impression recording for full screen ad formats:
Callback | Result |
---|---|
onAdOpened() | Impression recorded
|
onAdFailedToShow() | Impression failure1
|
None of the above for several seconds | Impression recorded
|
1 For failed impressions, your ad network is not charged for the impression, but it impacts your billable event rate adjustment. See bid request signals for more information.
The following mock example demonstrates a load/show lifecycle where an ad show call may result in a failure.
final class SampleRtbAdapter extends RtbAdapter implements MediationRewardedAd {
private MediationRewardedAdCallback callback;
private RewardedAd rewardedAd;
...
@Override
public void loadRewardedAd(
MediationRewardedAdConfiguration adConfiguration,
final MediationAdLoadCallback<MediationRewardedAd, MediationRewardedAdCallback> loadCallback) {
// Load an ad. This mock example uses Google's SDK, but in practice
// your adapter will load the ad using your ad network's SDK.
RewardedAd.load(adConfiguration.getContext(),
"ca-app-pub-3940256099942544/5224354917",
new AdRequest.Builder().build(),
new RewardedAdLoadCallback() {
@Override
public void onAdLoaded(@NonNull RewardedAd rewardedAd) {
// When the ad loads, invoke the load success callback.
callback = loadCallback.onSuccess(SampleRtbAdapter.this);
}
});
}
@Override
public void showAd(Context context) {
// In this mock example, your ad network requires an activity context, but
// didn't receive one, making you unable to show the ad.
if (!(context instanceof Activity)) {
AdError error = new AdError(1, "Context must be an activity",
"com.google.ads.mediation.sample");
callback.onAdFailedToShow(error);
}
// This example shows Google SDK's callbacks, but it's likely your SDK
// has similar presentation callbacks.
rewardedAd.setFullScreenContentCallback(new FullScreenContentCallback() {
@Override
public void onAdShowedFullScreenContent() {
// Your ad network SDK successfully showed the ad. Call onAdOpened().
callback.onAdOpened();
}
@Override
public void onAdFailedToShowFullScreenContent(AdError adError) {
// Your ad network SDK failed to show the ad, invoke onAdFailedToShow.
// In practice, you will map your SDK's error to an AdError.
AdError error = new AdError(adError.getCode(), adError.getMessage(),
adError.getDomain());
callback.onAdFailedToShow(adError);
}
});
rewardedAd.show((Activity) context, ...);
}
}