As of June 30th, 2022, the Sinch WhatsApp Business Messaging API does not check whether recipients have opted in or out before sending messages. It is the user's responsibility to ensure that the recipient has opted in before sending.
In order to collect, record, and act upon opt-out requests, you can include an opt-out button in any Marketing message templates you create. You can record the user's interaction with this button, and update your backend systems accordingly.
For more information on the opt-in and opt-out requirements for WhatsApp messages, see the WhatsApp Business Policy.
Learn more about the Sinch WhatsApp Business API.
