Are there any limits on how many messages I can send?

This article details the limits associated with the WhatsApp Sender extension.

There are no limits imposed by WhatsApp Sender on how many messages can be sent in a given licensed period.

However, WhatsApp Sender sends messages at a maximum rate of 9 messages per minute. This means that a maximum of 12,960 messages can be sent in a 24 hour period.

This send rate reduces the chances of your phone number being associated with a spammer by WhatsApp, and therefore helps to avoid your phone number being blocked. However, this send rate means that your messages may take a long time to be delivered if you plan to send more than 13,000 messages on a daily basis.