As announced previously , the Ad Exchange Buyer API  is set to sunset by the end of Q2, 2021. We will begin the process of phasing the API out on June 1st, where a small percentage of API requests will begin to return an API error response that includes details about the impending sunset. You can expect API errors to progressively increase leading up to the sunset date. Note that this sunset does not include the Ad Exchange Buyer II API , which is not deprecated at this time. Real-time Bidding API  is the replacement for the Ad Exchange Buyer API, and we encourage you to migrate before the sunset date in order to avoid interruptions to your integration. To learn more about the Real-time Bidding API, you can read the migration guide , reference documentation , and the new resource guides . Additionally, samples  for several programming languages are available to assist you with your migrations.support forums .