RunMQTT exposes secure endpoints for native MQTT clients and browser-compatible WebSocket clients.
Endpoints
| Transport | Endpoint form | Typical use |
|---|---|---|
| MQTT over TLS | mqtts://<broker>.tls-broker.runmqtt.com:8883 | Devices, gateways, and backend services |
| MQTT over secure WebSocket | wss://<broker>.tls-broker.runmqtt.com/mqtt | Browser applications and WebSocket-only networks |
Plaintext MQTT is not exposed as a customer endpoint. Always use the hostname shown in the dashboard so TLS certificate validation can succeed.
MQTT versions
The managed broker path supports MQTT 3.1.1 and MQTT 5.0. MQTT 5 support includes standard acknowledgement reason codes and commonly used publish properties such as Content Type, User Property, Response Topic, Correlation Data, and message expiry.
The built-in browser console currently uses MQTT 3.1.1 by design. It checks that credentials, endpoint routing, and basic topic permissions work; it is not a complete MQTT 5 protocol inspector.
Plan feature matrix
| Capability | Starter | Growth | Scale |
|---|---|---|---|
| MQTT 3.1.1 clients | Included | Included | Included |
| MQTT 5 clients | Included | Included | Included |
| QoS 0 and QoS 1 | Included | Included | Included |
| QoS 2 | — | Included | Included |
| Last Will messages | Included | Included | Included |
| Retained messages | — | Included | Included |
| TLS and WSS | Included | Included | Included |
Choosing QoS
- QoS 0 minimizes overhead for replaceable telemetry.
- QoS 1 is the default for events that must arrive but can be handled idempotently.
- QoS 2 is for Growth and Scale workloads with a measured exactly-once delivery requirement at the MQTT protocol boundary.
QoS does not replace application idempotency. Reconnects, downstream retries, and external systems can still produce duplicate business operations.
Retained and Last Will messages
A retained message stores the latest payload for a topic and sends it to new subscribers. It is available on Growth and Scale. Last Will messages notify subscribers when a client disconnects without completing a normal MQTT shutdown and are included in every plan.