Definition: https://en.wikipedia.org/wiki/Webhook
I was thinking of a 2 input form. 1 For the URL that would be POST too, and 1 for a Key which can be anything from a user input perspective. Send basic data, Price, Item, Receipt, Transaction ID, you dont even need to send the persons avatar information. Those 4 things would be awesome. Anyone with any sort of programming experience can utilize them.
I`ll gladly make a Example Node.js Server to demo the functionality if need be. But I think this is a REALLY much needed thing for Sansar to Start Early with.