MQTT Source Node
Quick Reference
Use Credentials Optional username/password credential for authenticated brokers. Leave blank for anonymous brokers.
Broker URL
The MQTT broker URL. Use ssl:// or wss:// when TLS is enabled.
ex: tcp://broker:1883 or ssl://broker:8883
Topic Filter
The MQTT topic filter to subscribe to. Supports + and # wildcards.
ex: sensors/#
Encoding Type The format of the incoming messages.
Client ID The MQTT client identifier used for the connection.
QoS
Quality of Service level: 0 (at most once), 1 (at least once), or 2 (exactly once). Default: 1.
Enable TLS
Use ssl:// or wss:// for the broker connection. Default: off.
Overview
The MQTT Source node lets your workflow subscribe to an MQTT broker and stream incoming messages into the pipeline. It acts as the starting point of your workflow, buffering messages received from the subscribed topic filter and passing each one downstream for processing.
It uses MQTT v5 and supports authenticated and anonymous brokers, configurable Quality of Service, TLS, and automatic reconnect.
Configuration
| Field | Description | Required | Default |
|---|---|---|---|
| Broker URL | The MQTT broker URL. Use ssl:// or wss:// when TLS is enabled (e.g. tcp://broker:1883, ssl://broker:8883). | Yes | — |
| Topic Filter | The topic filter to subscribe to. Supports + (single level) and # (multi level) wildcards (e.g. sensors/#). | Yes | — |
| Client ID | The MQTT client identifier used for the connection. | Yes | — |
| Encoding Type | Defines how each message should be interpreted. Options: CSV, JSON Object, JSON Array, JSON Lines, String Line, Text, XML. More info here. | Yes | — |
| Use Credentials | Select or create a username/password credential for authenticated brokers. Leave blank for anonymous brokers. | No | — |
| QoS | Quality of Service level: 0 (at most once), 1 (at least once), or 2 (exactly once). | No | 1 |
| Enable TLS | Use ssl:// or wss:// for the broker connection. | No | off |
Advanced settings
| Field | Description | Required | Default |
|---|---|---|---|
| Clean Start | Set the MQTT clean-start flag on connect. | No | on |
| Automatic Reconnect | Reconnect automatically after a dropped connection. | No | on |
| Session Expiry Interval (seconds) | MQTT session expiry interval. Leave blank for none. | No | — |
| Receive Timeout (ms) | How long a fetch waits for the first message before returning. | No | 1000 |
| Max Batch Size | Maximum number of messages returned per fetch. | No | 500 |
| Receive Queue Capacity | Bounded inbound queue size between the MQTT callback and the framework loop. | No | 10000 |
Related Nodes
- Kafka Source: Consume streaming data from Kafka
- SQS Source: Read messages from an Amazon SQS queue