Question:
If somebody opts in in messenger bot OTN, does that mean I can send ONE notification only or can I send Multiple Messages within the 1 year validity of the Token?
Answer:
OTN stands for “One Time Notification”. As the name suggests, it's only a one-time approval to send one message. You may create multiple OTN campaigns, and if you get approval for each of those campaigns, then you may send one message for each token approval that you receive. Please note that one token is equal to one message.
Before you can send One-Time Notifications, you need to be granted permission from Facebook to access the beta. Apply for this from 'Messenger Platform' > 'Advanced Messaging Features' For pages connected to Business Manager.
or through the 'Advanced Messaging' section of your Page Settings.
Also, be wary when using Message Tags. It must not be used incorrectly or in violation of the messenger policy.
To read more about message tags, please click here:
https://developers.facebook.com/docs/messenger-platform/send-messages/message-tags
You may also want to read an article we have written about this:
https://blog.marketingmaster.io/blog/how-to-safely-send-a-promotional-messenger-broadcast