The Social Media Pusher plugin forwards a published stream to another RTMP/RTMPS endpoint, such as social media (ie, Facebook, YouTube, etc). The plugin can be used through a REST call to Stream Manager, or else it can be used standalone on a single server. The URI of the request differs between these two methods.

Note that the Social Media Pusher API is deprecated (as of 14.1.0) in favor of the RTMP Push Restreamer which serves the same purpose.
RTMP Push Restreamer