Backendless features a powerful publish/subscribe (pub/sub) system with easy-to-use APIs. A pub/sub implementation consists of three components: publishers, subscribers, and a message broker (which in our case is Backendless). Your app can subscribe to receive messages using the Subscription API, and thus becomes a “Subscriber”. Publishers send messages using the Publishing API, and the backend delivers messages to subscribers. Message delivery can be unconditional, where all messages are delivered to subscribers, or conditional, where messages are only delivered if they match the subscription criteria. Backendless supports broadcasts, which deliver messages to multiple recipients, and point-to-point messaging, where a message is delivered to a single recipient.