If the business wants to send a message, and there is no open customer service window, then the business must use a message template. The message will be associated with a category (either utility, authentication, or marketing), and you will be charged based on the category of the message.
If there is an open customer service window, the business can respond using any message type. If you send a utility template message during this window, you will not incur charges for that message. If you send a template message in another category (authentication or marketing), and you will be billed accordingly.
Learn more about the Sinch WhatsApp Business API.
