EMQX vs Mosquitto

Overview

EMQX and Eclipse Mosquitto are both MQTT brokers, but they serve fundamentally different scales and use cases within the IoT ecosystem.

EMQX

Best for: Enterprise deployments, massive scale, high availability

Key Strengths:

• 100M+ concurrent connections per cluster
• Native clustering with masterless architecture
• 50+ built-in integrations (Kafka, databases, cloud services)
• SQL-based Rule Engine for in-flight processing
• Enterprise support and managed cloud options
• MQTT 5.0, QUIC, and WebSocket support

Trade-offs:

• BSL 1.1 license (clustering requires license as of v5.9.0+)
• Higher resource requirements
• Steeper learning curve

Mosquitto

Best for: Edge deployments, embedded systems, small-scale IoT

Key Strengths:

• Extremely lightweight (can run on Raspberry Pi)
• Eclipse Foundation project with open governance
• Simple configuration
• Low resource footprint
• Free for all use cases (EPL/EDL dual license)

Trade-offs:

• No native clustering (requires external solutions)
• Limited built-in integrations
• Single-node only
• No enterprise support

When to Choose EMQX

• You need 10,000+ concurrent connections
• High availability is critical
• You want built-in data integration
• You need enterprise support

When to Choose Mosquitto

• Edge or resource-constrained deployments
• Simple MQTT pub/sub without complex routing
• You prefer fully open-source licensing
• You have external tools for clustering/monitoring

Can They Coexist?

Yes. Many deployments use Mosquitto at the edge (on gateways or PLCs) and EMQX in the cloud as the central broker. This pattern leverages Mosquitto's small footprint for local aggregation while using EMQX for enterprise-scale data distribution.