Pubnub is described as 'Disc works in your device' and is an app in the Development category. There are more than 50 alternatives to Pubnub for a variety of platforms, including Online / Web-based, Windows, Linux, Mac and Android. The best alternative is Firebase, which is free. Other great apps like Pubnub are CONTUS MirrorFly (Paid), GUN (Free, Open Source), Supabase (Free, Open Source) and MongooseIM platform (Free, Open Source).
CONTUS MirrorFly is customizable communication APIs and SDKs for businesses to integrate or develop collaboration platforms with real-time chat, voice, video calling and video conferencing features on their existing web and mobile applications.
MongooseIM is aimed at large, complex enterprise level projects, where real-time communication is critical for business success. It provides high availability, ease of deployment, development and reliability in production.
deepstream.io is a clusterable realtime server that handles persistent tcp and websocket connections. It offers data-sync, pub/sub and request/response. It's available for Linux, Mac and Windows and comes with clients in JS, Java and many others.