EMQX

EMQX is a scalable MQTT broker and real-time messaging platform designed to connect large fleets of devices and stream data reliably to applications, clouds, and analytics systems. It supports modern MQTT features and provides operational tooling for running production IoT and IIoT deployments.

Key Features

• MQTT 5.0/3.1.1/3.1 broker with pub/sub messaging
• Protocol gateway support for MQTT-SN, CoAP, and LwM2M (via gateways)
• Masterless clustering for high availability and horizontal scalability
• SQL-based rules engine for filtering, transforming, and routing in-flight messages
• Built-in integrations/bridges to common databases and message queues
• Security features including TLS, X.509, JWT-based auth, and ACL-based authorization
• Management dashboard and HTTP API for administration and automation
• Observability integrations including Prometheus and OpenTelemetry

Use Cases

• IoT device connectivity and telemetry ingestion at scale
• Event-driven integration from MQTT topics to databases, queues, and webhooks
• Industrial and connected-vehicle messaging backbones with high availability

Limitations and Considerations

• Licensing changed to Business Source License (BSL) 1.1 for recent versions
• Operating large clusters requires careful capacity planning and monitoring

EMQX is a strong choice when you need a robust, production-ready MQTT backbone with clustering, security controls, and flexible routing/integration for real-time device data. It fits both edge-to-cloud pipelines and enterprise IoT deployments where reliability and throughput are critical.