MQTT

MQTT (Message Queuing Telemetry Transport) is the OASIS standard, lightweight, publish/subscribe protocol for machine-to-machine (M2M) communication, optimized for high-latency or low-bandwidth networks (IoT).

MQTT is the de-facto messaging standard for the Internet of Things (IoT), originally developed by IBM in 1999 for monitoring oil pipelines via satellite. The protocol employs a publish/subscribe architecture: clients connect to a central broker (e.g., Mosquitto, HiveMQ) and exchange messages via topics, enabling one-to-many communication. Its design is extremely lightweight; a minimal control message can be as small as two bytes, making it ideal for resource-constrained devices (microcontrollers, sensors). It provides three Quality of Service (QoS) levels (0: At most once, 1: At least once, 2: Exactly once) to ensure reliable delivery across unreliable networks. The latest version is MQTT 5.0, released in 2019, which added features like reason codes and shared subscriptions.

https://mqtt.org