push notification

https://github.com/darylrowland/react-native-remote-push

https://facebook.github.io/react-native/docs/pushnotificationios.html

Pubnub can also do realtime chat, but it's a relatively expensive service.

The node.js server can be augmented with socket.io and function as a real-time chat server.

Amazon SNS https://aws.amazon.com/sns/
https://aws.amazon.com/sns/pricing/ (faily cheap and works for all platforms, plus we'd get tech support at the loft)
https://aws.amazon.com/blogs/aws/push-notifications-to-mobile-devices-using-amazon-sns/

Parse push https://parse.com/products/push (lowest tier is free)
10 minute guide https://parse.com/tutorials/ios-push-notifications

Pubnub push https://www.pubnub.com/solutions/push-notifications/
https://www.pubnub.com/products/mobile-push/ pubnub is cool if we also want to delegate the real-time messaging feature off the rails app

urban airship https://www.urbanairship.com/products/platform

Ruby gem for ios push notifications https://github.com/grocer/grocer (maintained)

Node.js server for push notifications https://github.com/jazzychad/PushServer deploy configure and it's done

https://www.pushwoosh.com/

https://www.kahuna.com/products/

https://boxcar.io/developer

realtime backend solutions

http://swarmjs.github.io/articles/todomvc/

http://deepstream.io/

very good blog detailing a cto's experience building a chat app https://medium.com/@davidbyttow/scaling-secret-real-time-chat-d8589f8f0c9b Ends up recommending pusher It’s often unwise to roll your own implementation, no matter how fun it might be (obviously, but we all keep doing it!)
http://developers.planningcenteronline.com/2014/09/23/live-updating-rails-with-react.js-and-pusher.html
https://pusher.com/pricing

reverse proxy to enable real-time features on any backend http://pushpin.org/

MIT licensed meteor chat backend https://github.com/RocketChat/Rocket.Chat
https://rocket.chat/

https://layer.com/

Meteor + React Native http://blog.differential.com/meteor-react-native-learning-from-experience/

https://github.com/realtime-framework/RCTRealtimeMessagingIOS

http://firehose.io/

https://github.com/tackk/react-native-pusher