VerneMQ

VerneMQ is a high-performance, distributed MQTT message broker designed for scalable, highly available messaging in IoT, M2M, mobile, and web applications. Built on Erlang/OTP, it supports clustering, low-latency publish/subscribe, and fault tolerance on commodity hardware.

Key Features

• MQTT 3.1, 3.1.1, and MQTT 5.0 protocol support (including QoS 0/1/2)
• Horizontal and vertical scaling with clustering and high availability
• TLS encryption and WebSocket support for MQTT over the web
• Authentication and authorization via built-in plugins and extensible hooks
• Multiple integration options including database-backed auth and HTTP webhooks
• Offline message storage and session handling features such as shared subscriptions and session balancing
• Administration HTTP API and operational visibility features (logging, tracing, status page, $SYS tree)

Use Cases

• Reliable IoT device connectivity for telemetry ingestion and command/control
• Industrial and smart infrastructure messaging with high availability requirements
• Mobile and web realtime messaging based on MQTT publish/subscribe

Limitations and Considerations

• Advanced customization may require writing plugins or Lua scripts depending on integration needs
• Some features (for example, offline storage) rely on specific backend components such as LevelDB

VerneMQ is a solid choice when you need a production-grade MQTT broker that can handle large connection counts and tolerate network failures. Its clustering model, plugin architecture, and integration options make it suitable for both lab deployments and industrial-scale systems.