What is MQTT?

MQTT (Message Queuing Telemetry Transport) is a lightweight publish/subscribe messaging protocol designed for constrained devices and low-bandwidth networks. It is widely used in smart home and IoT applications.

How It Works

1. A broker (server) sits at the center — e.g., Mosquitto
2. Devices publish messages to topics (e.g., home/living-room/temperature)
3. Other devices subscribe to topics to receive updates
4. The broker routes messages from publishers to subscribers

Why Use MQTT?

• Lightweight: Minimal overhead, suitable for microcontrollers
• Reliable: Supports QoS (Quality of Service) levels 0, 1, and 2
• Real-time: Near-instant message delivery
• Decoupled: Publishers and subscribers don’t need to know about each other

Common Smart Home Uses

• Zigbee2MQTT: Bridges Zigbee devices to MQTT
• Tasmota: ESP-based firmware that speaks MQTT natively
• Home Assistant: Full MQTT integration for device control
• ESPHome: Generates firmware with MQTT support for ESP devices