If you do not want your APIs to be called over the Internet, you can disable access over the Internet for the API group to which your APIs belong. This way, callers can call your APIs only over a virtual private cloud (VPC). Procedure:
Log on to the API Gateway console. In the left-side navigation pane, choose Open API > API Groups.
Click the API group that you want to manage on the API Groups page. The Group Details page appears.
In the Basic Information section, find the public second-level domain name of the API group, and click Disable Access over Internet on the right.
After you disable access over the Internet, all requests from the Internet, including those from custom domain names, are denied, and API calls have to be initiated from internal domain names.
The API Gateway console does not support API debugging based on internal domain names.