The CommerceV3 software has been updated to allow the use of a Gift Certificate API for query by CV3.
The API can be set in Settings> Options> Gift Certificate Options> Gift Certificate Web Service.
The API functions similar to the other gift card processors, using the web service to request balance inquiries and decrement the card value.
The API specifications are available at the following link:
http://docs.commercev3.com/index.php/Gift_Certificate_API_Specs