PubNub Chat delivers messages in realtime in less than 100ms globally regardless of where your users are connecting from. As messages are published on the network they are replicated to 15+ points of presence within milliseconds. The clients can subscribe to channels to receive these messages instantly or use the History API to fetch past messages from our storage.
Note: It is recommended to publish messages directly from a client application to PubNub so other clients can receive the messages quickly. Publishing messages by sending them to a server can add significant delays and reduce performance.