EMQX vs HiveMQ Community Edition

Scaling past one EMQX node is a licensing decision before it is an architecture decision. From EMQX 5.9.0, deploying a cluster of more than one node requires loading a license file, while the EMQX license permits production use of a single node provided it is not offered to third parties on a hosted or embedded basis. Once licensed, EMQX offers masterless clustering, so there is no single coordinator node to designate. Before you size the cluster, confirm with EMQX which license terms apply to your deployment, including how the license file is issued and renewed, and test how the cluster handles node loss at your expected connection counts and message rates.

HiveMQ CE follows a different path. The CE README does not list clustering among its features, so a multi-node deployment should not be planned on the open-source edition alone. Scaling beyond one node means moving to the commercial HiveMQ Broker, which HiveMQ lists with masterless dynamic clustering, zero-downtime upgrades and disk replication. Treat those three features as the scope to evaluate in writing. Ask HiveMQ what each one means in its support terms, which versions carry them, and what it requires from your infrastructure, since a commercial subscription changes both your cost model and your upgrade path.

Whichever broker you choose, load balancer placement and session handling decide how the cluster behaves when a node fails. Place the balancer in front of the MQTT listeners, and confirm each vendor's guidance on connection draining, sticky routing and whether persistent sessions survive a node change. Ask both vendors in writing how client sessions, retained messages and in-flight QoS 1 and QoS 2 messages move between nodes, what clients must do on reconnect, and what failover time they measure in their own tests. Then run a failover test with your actual device reconnect logic before you fix the node count and hardware.

The effort on an MQTT rollout rarely sits in installing the broker. It sits in device identity, access rules, data pipelines, load validation and cluster sizing, and each of these grows with the number of device types and the number of systems downstream. On EMQX, device authentication may combine username and password, JWT, PSK and X.509 certificates over TLS, so the design work is deciding which device classes use which method, how certificates are issued and rotated, and how JWT claims map to permissions. On HiveMQ CE, the Java extension SDK covers authentication and authorization, so the equivalent work is writing and testing that custom logic yourself. Ask each vendor, and your own security team, which identity method each device fleet will use before any project plan is accepted.

Access control and extension logic are the next drivers. On EMQX, topic-level rules are commonly expressed through its authorization chain and SQL-based rule engine, while on HiveMQ CE, authorization and packet interceptors are written as Java code that you own, test and upgrade. Integration pipelines to Kafka or databases add another layer, since each target needs schema decisions, retry behavior and monitoring. Load testing against your target connection count is the step most often cut short, and it should use realistic reconnect storms and QoS levels rather than a simple publish benchmark. Cluster sizing then follows from those results. Note that EMQX requires a license file before a multi-node cluster can run, and HiveMQ clustering sits in the commercial HiveMQ Broker, so confirm the licensing path before sizing. DeployOpen plans and implements this work inside your own cloud accounts, data centers or air-gapped networks under a written, fixed-scope agreement, and no duration is given here; the scope document should list each identity method, integration target, test profile and cluster topology so the quote reflects them.

Start with the EMQX repository README on GitHub, which lists the protocol support, the masterless clustering, the rule engine and the 50-plus data integrations that this comparison relies on. Treat it as a feature inventory, not a commitment. Confirm the MQTT 5.0 behavior, the gateway list (MQTT-SN, CoAP, LwM2M) and the authentication options against the documentation for the exact version you plan to run. Then open the LICENSE file, which governs the Business Source License terms: the single-node production grant, the restriction on offering EMQX to third parties on a hosted or embedded basis, and the four-year conversion to Apache 2.0 for each release.

Next, read the EMQX releases page to see which version your team would pin, when it was published and what changed. Because the license terms attach to each published release, the release date matters for the conversion clock as well as for security fixes. Compare that page against the HiveMQ CE README on GitHub, which confirms the Apache 2.0 license, MQTT 3.x and MQTT 5 support, the Java extension SDK and the Java 11 minimum. The README does not list clustering as a feature, so ask HiveMQ in writing whether any clustering exists in the Community Edition before you design around it.

Finally, check the HiveMQ CE releases page for the current build and its publication dates, and open the HiveMQ Broker product page on hivemq.com to see which clustering, zero-downtime upgrade and disk replication features belong to the commercial broker. Record the sources and versions you verified in your architecture decision record. If the clustering requirement is firm, the decision is between an EMQX license file for a multi-node cluster and the commercial HiveMQ Broker, and both need a written confirmation of terms before procurement.