The Vapi Client SDKs automatically configure audio streaming to and from the client, and provide a simple interface for starting calls. The interface is equivalent across all the SDKs.

The SDKs are open source, and available on GitHub:


  • speech-start, speech-end, and volume-level for creating animations. - message for receiving messages sent to the Server URL locally on the client, so you can show live transcriptions and use function calls to perform actions on the client.