MQTT 3.1.1 & 5.0
Lightweight pub/sub for IoT, mobile, and millions of concurrent connectionsTiny binary frames (2 bytes header), persistent sessions across disconnects, retained messages, last-will-and-testament for unreliable networks. The de-facto standard for IoT telemetry and mobile push.
- QoS 0 / 1 / 2 — at-most-once, at-least-once, exactly-once delivery
- 5.0 properties — topic aliases, message expiry, response topics, user properties
- Shared subscriptions — load-balance one topic across worker pools (5.0)
- Brokers tested — HiveMQ, Mosquitto, EMQX, AWS IoT Core, Azure IoT Hub