This feature requires a Vimeo Enterprise plan.
At this time, only Vimeo Enterprise users can access the Vimeo Live API endpoint. Learn more about Enterprise plans at 'What's included with Vimeo Enterprise?'.
Technical documentation of the Live API is found on the Developer Site at 'Working with Vimeo Live'.
Enterprise users who need access to the Live API, or require assistance with using the API, should contact their account manager for support.