Here is an example of how to ask users to opt-in to receive broadcasts.
Ask user a question in your welcome message, and save the answer to a user attribute. You can do it by using either
“Quick Reply” or “Set up user attribute” plugin:
If your bot has already been launched and has an audience, you may need to send them a broadcast with the same question.
Then, when setting up a broadcast, click the User Filter button to open user filter settings:
Select only those who opted-in:
Now you can send unlimited broadcasts to these users.
Note that according to Facebook’s Policy, after users interact with your bot, you may only message people / send a broadcast within 24 hours of such interaction (apply within 24h window attribute in user filter).
In addition to that, and until the next interaction, you may send one additional message after this 24 hour period in order to follow up on your conversation.
However, you may send broadcasts at any time to those users who specifically opt-in to receiving such content, as described above.