Protocols

What is MQTT?

Short answer

MQTT (Message Queuing Telemetry Transport) is a lightweight pub/sub messaging protocol built for devices with limited bandwidth and unreliable networks. A central broker receives publications to topics and distributes them to subscribers. It's the de-facto IoT standard because of its low overhead and three QoS levels.

Pub/Sub with a broker

Devices don't talk to each other: they publish to 'topics' (e.g. 'fleet/truck01/speed') and a broker dispatches to whoever is subscribed. This decoupling lets you scale to thousands of sensors and multiple consumers without touching the device.

The three MQTT QoS levels

QoS 0: 'fire and forget', may be lost. QoS 1: at least once (possible duplicates). QoS 2: exactly once, more overhead. On cellular IoT, QoS 1 is the usual sweet spot.

Security and authentication

MQTT over TLS with client certificates (mutual TLS) is mandatory in production. User/password without certificates isn't enough. The broker must support credential revocation and per-topic authorization.

Broker centralizes pub/sub
Hierarchical topics
QoS 0/1/2 by criticality
Mutual TLS with certificates

Tailored offer

Production-ready MQTT template

Download our template: topic structure, recommended QoS, X.509 auth model, and client/broker code example.

Frequently asked questions

MQTT or HTTPS for my sensor?+

MQTT if you transmit often or keep the session open; saves bytes and battery. HTTPS if you report once a day or need existing REST integrations.

Is MQTT-SN the same thing?+

MQTT for Sensor Networks is the variant for non-TCP networks (Zigbee, 802.15.4). Same idea, adapted protocol. Uncommon on cellular IoT.

Which broker should I use?+

Self-managed: Mosquitto or EMQX. Cloud: AWS IoT Core, Azure IoT Hub, HiveMQ Cloud. Pick by scale and integration needs.