---
title: mqtt.to() function
description: >
  `mqtt.to()` outputs data from a stream of tables to an MQTT broker using MQTT protocol.
menu:
  flux_v0_ref:
    name: mqtt.to
    parent: experimental/mqtt
    identifier: experimental/mqtt/to
weight: 201
flux/v0/tags: [mqtt, outputs]
---

<!------------------------------------------------------------------------------

IMPORTANT: This page was generated from comments in the Flux source code. Any
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To make updates to this documentation, update the function comments above the
function definition in the Flux source code:

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Fluxdoc syntax: https://github.com/influxdata/flux/blob/master/docs/fluxdoc.md

------------------------------------------------------------------------------->

`mqtt.to()` outputs data from a stream of tables to an MQTT broker using MQTT protocol.



##### Function type signature

```js
(
    <-tables: stream[A],
    broker: string,
    ?clientid: string,
    ?name: string,
    ?password: string,
    ?qos: int,
    ?retain: bool,
    ?tagColumns: [string],
    ?timeColumn: string,
    ?timeout: duration,
    ?topic: string,
    ?username: string,
    ?valueColumns: [string],
) => stream[B] where A: Record, B: Record
```

{{% caption %}}
For more information, see [Function type signatures](/flux/v0/function-type-signatures/).
{{% /caption %}}

## Parameters

### broker
({{< req >}})
MQTT broker connection string.



### topic

MQTT topic to send data to.



### qos

MQTT Quality of Service (QoS) level. Values range from `[0-2]`. Default is `0`.



### retain

MQTT retain flag. Default is `false`.



### clientid

MQTT client ID.



### username

Username to send to the MQTT broker.

Username is only required if the broker requires authentication.
If you provide a username, you must provide a password.

### password

Password to send to the MQTT broker.
Password is only required if the broker requires authentication.
If you provide a password, you must provide a username.



### name

Name for the MQTT message.



### timeout

MQTT connection timeout. Default is `1s`.



### timeColumn

Column to use as time values in the output line protocol.
Default is `"_time"`.



### tagColumns

Columns to use as tag sets in the output line protocol.
Default is `[]`.



### valueColumns

Columns to use as field values in the output line protocol.
Default is `["_value"]`.



### tables

Input data. Default is piped-forward data (`<-`).




## Examples

### Send data to an MQTT broker

```js
import "experimental/mqtt"
import "sampledata"

sampledata.float()
    |> mqtt.to(
        broker: "tcp://localhost:8883",
        topic: "example-topic",
        clientid: r.id,
        tagColumns: ["id"],
        valueColumns: ["_value"],
    )

```