---
title: "MQTT Transmit"
slug: "mqtt-transmit"
updated: 2023-10-25T10:30:46Z
published: 2023-10-25T10:30:46Z
canonical: "docs.sightmachine.com/mqtt-transmit"
---

> ## Documentation Index
> Fetch the complete documentation index at: https://docs.sightmachine.com/llms.txt
> Use this file to discover all available pages before exploring further.

# MQTT Transmit

A mqtt data transmit transfers data to the mqtt broker.

**Example:**

If we want to upload our records from the bathhouse:water stream to our IOT cloud, broker.emqx.io with port 1883 our configuration will look something like this:

```actionscript
{
    "data_transmit": [
        {
            "transmit_name": "iot_hub_transmit",
            "transmit_type" : "mqtt",
            "filter_stream": [
                "bathhouse:water"
            ],
            "host": "broker.emqx.io",
            "port": 1883,
            "username": "spiderman",
            "password": "somepowerfullpass",
            "topic": "some_topic",
            "client_id": "some_client_id"
        }
    ]
}
```

**Warning:**

This plugin is very sensitive to upload bandwidth: if it can’t upload a payload completely within the timeout, it will abort the connection and try again. You may need to increase the timeout from the default of two minutes. For example:

```actionscript
{
    "transmit_name": "SightMachine",
    "transmit_type": "mqtt"
    "filter_stream": ["*"],
    "timeout": 300
}
```

**Configuration:**

**Required** and *optional* properties that can be configured for an MQTT transmit:

- **host**: MQTT broker hostname (e.g. broker.emqx.io)
- **port**: MQTT connection port (Currently defaults to 1883)
- *client_id*: Some unique string identifying the client to the MQTT server. Must be unique across all connections to the MQTT server.
- *username*: Username to connect to the server
- *password*: Password to connect to the server
- **topic**: topic where we send MQTT messages
- *additional_fields*: additional field to add in the message payload for e.g. { “processingPath”: “SM”}
- **transmit_name**: ID for the transmit. It must be unique.
- **transmit_type**: Method to use in transmitting records.
- **filter_stream**: A list of streams that will use the transmit. Each stream can either be * (all) or asset:stream.
- *timeout*: Number of seconds to wait until timing out.
- *poll_interval*: Maximum number of seconds to wait between requests
- *max_request_records*: Maximum number of records to send in a single request.
- *max_request_size_bytes*: Maximum number of bytes allowed in a single request. Size is capped at 4 MB.
- *opc_payload_metadata*: Additional fields to add in the OPC-formatted payload. E.g. { “TiqTwin”: { “NodeId”: “a2ec725a-78e2-431b-a124-ce20b8e3e4c6” }} Ignored if use_opc_publisher_format is False.
- *opc_message_metadata*: Per-message metadata fields to add in the OPC-formatted payload.
- *use_opc_publisher_format*: If True, the message payload will be formatted to mimic OPC Publisher. [https://github.com/Azure/Industrial-IoT/tree/main/docs/opc-publisher#opc-publisher-telemetry-formats](https://github.com/Azure/Industrial-IoT/tree/main/docs/opc-publisher#opc-publisher-telemetry-formats)