Publish Subscribe

https://www.pubnub.com/blog/2014-08-21-amazon-sns-pubnub-differences-pubsub/

Conversely, PubNub supports an unlimited number of PubNub channels. This allows every end-user device to have its own channel for one-to-one connectivity.

https://www.quora.com/What-are-the-competitive-advantages-of-Pusher-vs-PubNub

https://pusher.com

https://www.pubnub.com/