Duplicate Pinterest Facebook invite functionality

Question

I'm trying to duplicate Pinterest's "Invite Friends" functionality. In case you haven't seen what it looks like, it looks like this:

This important points here are 1) there are multiple recipients and 2) you can type a custom message.

So far, with the Facebook API, I've only found ways to send a custom message to a single user or send a pre-canned message to multiple users. I haven't found a way to send a custom message to multiple users.

Here's what will let you send a custom message to just one user: https://developers.facebook.com/docs/reference/dialogs/send/

And here's what will let you send a pre-canned message to multiple users: https://developers.facebook.com/docs/reference/dialogs/requests/

So how are they doing it? How can I allow my user to send a custom message to multiple recipients like Pinterest is doing?

Answer 1

Facebook responded to a bug report about this about a week ago, stating it was "by design". Pinterest, among other apps, are whitelisted to be able to include multiple recipients. How to get whitelisted? Beyond me.

See https://developers.facebook.com/bugs/314701778595814 for full official response from Facebook (and frustrated responses by developers).