Connectors

Messaging & Event Streaming

MQTT

Lightweight pub/sub messaging for IoT: publish and subscribe to broker topics
MQTT specificationAPI checked August 18, 2026
Signs in with
Connection details
Runs on
Cloud or On-Prem Worker
Operations
2
Ready-made triggers
0

Connect MQTT

  1. In Neblex open Connect › Connections and click New Connection.
  2. Search for MQTT and give the connection a clear name.
  3. Fill in the fields. Secret values are encrypted and never shown again.
  4. Click Test, then Create Connection.
If the system is only reachable inside your network, choose an On-Prem Worker under Test from and run the flow on that Worker. See On-Prem Workers.
FieldWhat to enter
Connection setupRequired
HostRequired
PortOptionalExample: 8883
UsernameOptionalOptional MQTT 3.1.1 user name. A username without a password is valid; a password without a username is rejected.
PasswordOptionalSecretOptional sealed MQTT password bytes represented by the connection URL. It is used only when Username is present.
Use TLSOptionalTurning this off sends traffic and credentials without transport encryption. Use plaintext only for a customer-controlled endpoint that explicitly requires it.
Connection stringRequiredSecretPaste a root-only mqtt://, mqtts://, ssl://, or tls:// broker URL. Paths, queries, fragments, and password-only userinfo are rejected.

Use it in a flow

  1. Open a flow, open the node library and search for MQTT.
  2. Drag it onto the canvas and choose an Operation and your connection.
  3. Map the operation's fields from earlier steps, or click Map with Matt.
  4. Use Test this step to see what it returns, then save.

To start a flow from MQTT without a ready-made trigger: a Live stream trigger with MQTT as the stream source starts a run for each message as it arrives (see Streaming triggers).

Operations

2 operations in 2 groups. Each one is a step you can add to a flow.

Connection1
Test the connectionpingComplete an MQTT 3.1.1 CONNECT/CONNACK exchange with the configured broker.
Message1
Publish a messagepublishPublish byte-exact application data to an MQTT 3.1.1 topic and wait for the QoS-defined completion boundary.