Cartesia AI voices gives you the option on their website to change the speed and emotion of the voice, but I can't find this option on Vapi. I can see in the Cartesia AI documentation that it can be passed in the API request using "__experimental_controls," but is there any way I can add this to Vapi or is there an option somewhere I can change?

@Andrew Lowe Currently, VAPI integrates with various voice providers, and while some features like speed and emotion adjustments are available directly on the providers' platforms, they may not always be directly accessible through VAPI's interface. However, if Cartesia AI supports these features through their API using the

__experimental_controls

parameter, you can utilize these features by including the necessary controls in your API requests to VAPI, provided that VAPI supports passing custom parameters to the voice provider's API. If you're looking to include these controls in your requests and can't find the option in the VAPI interface, you might need to do this programmatically by editing the API request payload to include the

__experimental_controls

parameter with the desired settings for speed and emotion. If you need assistance with how to format your request or if you're unsure whether VAPI allows passing these custom parameters, please ask support for more info on this. They can provide you with detailed instructions or inform you about any updates that might have introduced these features directly in the VAPI interface.

Could you give me the link to any documentation that explains how to include custom parameters in my API requests to VAPI, please? And also, if you could explain how VAPI allows the passing of custom parameters so that I can include this in my API call.

@Andrew Lowe I'm here to help guide you through the process of including custom parameters in your API requests to VAPI. Unfortunately, I don't have the ability to provide direct links, but I can certainly explain how you might go about including custom parameters like

__experimental_controls

in your API calls. When you're constructing an API request to VAPI, you can typically include custom parameters in the JSON payload of your POST request. Here's a general example of how you might structure your request with custom parameters:

json
{
  "voiceProviderOptions": {
    "__experimental_controls": {
      "speed": "fast",
      "emotion": "happy"
    }
  },
  // ... other necessary parameters for your API call
}

In this example,

voiceProviderOptions

is a hypothetical object where you can specify provider-specific options, such as Cartesia AI's

__experimental_controls

. Please note that the actual structure and the name of the object where you include custom parameters may vary based on VAPI's implementation. To include these custom parameters in your VAPI calls, you would need to refer to VAPI's official documentation or contact their support team to get the exact details on how to structure your request. They will provide you with the correct field names and the expected format for including such custom parameters. If VAPI supports passing through custom parameters to the voice provider, following their documentation will allow you to adjust the speed and emotion of the voice as supported by Cartesia AI. If you're unable to find this information in the documentation or if you're unsure about the process, please reach out to VAPI's support team for further assistance. They will be the best resource for providing you with accurate and up-to-date information on how to use their API to its fullest potential.

as of now there is no option to pass these parameters, but you can raise the feature request over here: https://vapi.canny.io