Pub/Sub (Publish-Subscribe)

Messaging pattern where senders (publishers) don’t send directly to receivers (subscribers). Instead, all messages go through a broker which routes them by topic.

Publishers: send messages to a named topic Subscribers: register interest in a topic; broker delivers matching messages Broker: routes messages from publishers to subscribed clients

Key property: publishers and subscribers are decoupled — they don’t need to know about each other, don’t need to be online simultaneously (with persistent sessions).

Contrast with Request/Response (HTTP): client must initiate, server responds immediately.

MQTT uses pub/sub. Azure IoT Hub endpoints also follow pub/sub semantics.

See Also