Increase the conversion/customer satisfaction by a personalized Facebook Message by the Bot when a user comments/likes on your page - How to reply to a like/comment automatically with an Intelligence behind

Business Case : Users may like your page or leave a comment or your Ad, or some post and expect A personalized message to these users/customers can lead to a potential conversion in addition to customer satisfaction.
e.g.
A customer asks a question over a post on your FB page
A customer likes a post, and you want to generate a sales lead by approaching this customer

There can be lot of interesting use cases with the customer likes, comments etc.

How to do it?
Either you can choose the paid route for FB Ads and use the way out mentioned in FB docs.
Or
You can choose a free but a programmatic way to do so.

Solution:
Step 1: In your FB App Messenger web-hook settings, subscribe the events on page as in the video below.

Step 2 : Read about "feed" object and check the JSON received in the webhook you defined for Facebook. Feed refers to changes to a page's feed, such as posts, shares, likes, etc. The values received depend on the types of changes made to the page's feed.

Step 3 : Implement relevant calls for FB Graph Send Message or any action you want to do once you capture the event.  If you want to use AI on every comment, you can send the text from the feed to the AI engine ( in our case dialog flow or api.ai ) and get an answer for the user. Make sure to sen the page specific user ID in the call to AI, so that the response message is sent to correct user.

Good luck !