The Entitlement API is a crucial component of the Meta Quest Store's app verification process. It allows developers to check whether a user has purchased or obtained their app legitimately, ensuring that only authorized users can access the app. The API must be called within 10 seconds of the user launching the app and does not require internet connectivity. In the event of a failed entitlement check, developers are responsible for handling the error in their app code, such as by displaying an error message and quitting the app. This API plays a vital role in maintaining the security and integrity of the Meta Quest Store ecosystem. See more details here.