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IoTProtocolsArchitecture

MQTT vs WebSocket: Choosing Your IoT Protocol

Engineering Team·

Choosing the right communication protocol is one of the most important decisions in any IoT project. Here's our framework for choosing between MQTT and WebSocket.

MQTT

MQTT is a publish-subscribe protocol designed for lightweight machine-to-machine communication. It's ideal for IoT because:

  • Minimal bandwidth — Fixed header is only 2 bytes
  • QoS levels — At-most-once, at-least-once, exactly-once delivery
  • Last Will — Detect disconnected devices automatically
  • Retained messages — New subscribers get the last published value

When to use MQTT

  • Battery-powered devices with intermittent connectivity
  • Sensor networks with many publishers and few subscribers
  • Scenarios where you need guaranteed message delivery
  • Edge devices with limited processing power

WebSocket

WebSocket provides full-duplex communication over a single TCP connection. It's ideal for:

  • Real-time dashboards — Live updates without polling
  • Bidirectional streaming — Server and client can push at any time
  • Rich media — Can handle binary frames and large payloads
  • Browser-native — No additional client library needed on web

When to use WebSocket

  • Web-based monitoring dashboards
  • Applications requiring low-latency server-to-client pushes
  • Scenarios where you're already using HTTP infrastructure
  • When you need to stream audio, video, or binary data

Decision Framework

Consider MQTT if: Your devices are resource-constrained, intermittent, or you need pub/sub semantics.

Consider WebSocket if: You're building a real-time web UI, need bidirectional streaming, or your devices have reliable connectivity.

Hybrid approach: Use MQTT for device-to-cloud communication and WebSocket for cloud-to-dashboard. This is our recommended architecture for production IoT systems.