Glossary
MQTT (Message Queuing Telemetry Transport)
A lightweight publish and subscribe messaging protocol designed for constrained devices and unreliable networks, widely used in IoT and telemetry.
General definition
MQTT, short for Message Queuing Telemetry Transport, is a lightweight messaging protocol built around the publish and subscribe pattern. Clients publish messages to named topics, and a central broker forwards each message to every client subscribed to that topic. Publishers and subscribers never need to know about each other.
MQTT was designed for low-bandwidth, high-latency or unreliable networks and for devices with limited power and memory, which is why it dominates IoT and telemetry. It offers three quality-of-service levels:
- QoS 0, at most once, fire and forget
- QoS 1, at least once, delivery confirmed but duplicates possible
- QoS 2, exactly once, the strongest and most costly guarantee
Features like retained messages and last will and testament let subscribers get the latest state and detect when a device drops off.
MQTT vs chat protocols
MQTT and chat protocols such as XMPP both move messages in real time, but they optimize for different worlds. MQTT is tuned for machine-to-machine telemetry at massive fan-out with tiny payloads. Chat protocols add presence, rooms, history and human-centric semantics. Some platforms use MQTT under the hood for mobile push and presence because of its efficiency on unreliable mobile networks.
MQTT in the Ethora ecosystem
Ethora focuses on human and AI-agent messaging built on XMPP and the Ethora Chat Protocol rather than device telemetry. For IoT-style use cases, MQTT and Ethora are complementary: MQTT can carry device signals, while Ethora carries the conversation, notifications and AI agents that people interact with. Both can run on your own infrastructure for full data control.
