### Answer
Currently, Vapi specifically supports integration with Play.ht for custom voices, as outlined in the documentation [(1)](
) . There is no mention of support for a separate provider named "play.ai" in the available documentation, and all integration processes and API key configurations described are solely for Play.ht.
If you are encountering a 401 error with an API for "play.ai," it might be due to this service not being supported or integrated into the Vapi platform as per the current setup and documentation provided.
For voices supported and how to integrate them using Play.ht with Vapi, you can refer to the guide on setting up PlayHT Custom Voice .