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Plugin Catalog

This catalog collects plugin-specific documentation for custom EMQX plugins maintained outside the built-in product documentation.

EMQX plugins are typically built when standard product features do not fully meet a requirement, or when a domain-specific problem is better solved as an extension rather than as a built-in capability.

Some plugins remain specialized, while others may later be promoted into standard EMQX features if they prove useful across a broader range of real-world use cases.

The plugins listed on this page are maintained as part of the emqx.git monorepo.

Security

EMQX ACME Plugin

This plugin automatically issues and renews TLS certificates for EMQX SSL listeners through ACME-compatible certificate authorities such as Let's Encrypt.

Operations

Hot Upgrade (Relup)

This plugin applies .relup code-change instructions to a running EMQX node, allowing operators to roll out patched releases without restarting the VM.

Backup Sync

This plugin periodically synchronizes selected backup data from a primary EMQX cluster to a secondary cluster using the Data Backup APIs, keeping the secondary in step for disaster recovery.

Data Integration

MQTT Bridge with Disk Queue

This plugin forwards local MQTT messages to another MQTT broker, buffering them on disk for better resilience across network interruptions.

Mapping Tables

This plugin provides named mapping tables for Rule SQL, allowing rules to replace long CASE WHEN expressions with table lookups.

Message Persistence

Offline Messages

This plugin persists MQTT messages to MySQL or Redis so that subscribers can retrieve them after they reconnect, beyond what standard MQTT session persistence provides.

Messaging

Sync Request

This plugin lets an HTTP caller publish one MQTT request through the EMQX REST API and wait synchronously for the first matching MQTT response.

Connection Management

Per-username Session Quota

This plugin enforces a per-username session quota across the cluster, rejecting authentication with quota_exceeded once a username reaches its configured limit.

Namespace Governance

UNS Governance

This plugin enforces a Unified Namespace (UNS) topic structure and can validate the payloads of messages published to topics governed by UNS Governance.