### Answer
Vapi doesn't directly provide a feature to limit API usage by phone number or through other specific limits in its documentation. However, you may consider implementing application-level controls or logic to monitor and manage usage based on your requirements. This could include setting up your server logic to track call frequencies or durations from specific numbers and apply your own limits or thresholds.
For details on managing phone numbers and their configurations, you might find resources like [Buy Phone Number](
) [(1)](
) , [Update Phone Number](
) [(2)](
) , and [Delete Phone Number](
) [(3)](
) useful for managing phone numbers in Vapi. For broader control and management of your Vapi setup, reviewing the documentation on [Assistants](
) [(4)](
) and [Calls](
) [(5)](
) might also be beneficial.
Remember, directly managing API limits or implementing specific usage cap features would likely involve developing custom logic within your application infrastructure, possibly using the server URLs and metadata features provided by Vapi for deeper integration and control.