---
title: Sinks
slug: reference/sinks
docTags: 
createdAt: 2025-09-08T13:50:47.619Z
---

When creating a sink, the following fields are available:

## General

### Name

**Description:** Enter a unique name

### Description

**Description:** Optionally enter a description *(Optional)*

### Sink type

**Description:** Select a sink type

## SparkplugB

### NodeID

**Description:** Enter a NodeID to connect to

### GroupID

**Description:** Enter a GroupID to connect to

### MqttURL

**Description:** Enter the URL of the MQTT broker to connect to

### ClientCertificateFile

**Description:** Enter the client certificate file location if applicable

### ClientKeyFile

**Description:** Enter the client key file location if applicable

### Username

**Description:** Enter the username

### Password

**Description:** Enter the password

### KeepAliveSecs

**Description:** Enter the keep alive period (in seconds)
**Default:** 30

### QOS

**Description:** The QOS with which to publish. *(Optional)*
**Default:** 0
**Minimum:** 0
**Maximum:** 2

### MaxMetricsPerMessage

**Description:** Optionally, enter the max amount of metrics to send per message. By default this is set to 0, which means no limit. *(Optional)*
**Default:** 0

### DataOnly

**Description:** Optionally toggle DataOnly mode. When enabled no birth or death messages will be sent, only data messages will be sent. *(Optional)*
**Default:** false, so birth and death messages are sent

### EnableBuffer

**Description:** Optionally enable the buffer, if enabled, the sink will buffer messages when the MQTT broker is not reachable. *(Optional)*
**Default:** disabled

### BufferProcessInterval

**Description:** Process interval (in milliseconds): The interval at which the buffer is processed. *(Optional)*
**Default:** 250

### BufferMaxBatchSize

**Description:** The maximum number of messages in a batch, the batch size determines how many messages are sent in one go. *(Optional)*
**Default:** 5000

### BufferMaxBatches

**Description:** Max batches: The maximum amount of batches to keep in memory, when the maximum is reached a batch will be saved to disk if the disk queue is enabled and there is space available. *(Optional)*
**Default:** 20

### BufferDiskBatches

**Description:** Disk batches: The maximum amount of batches to write to a single file on disk *(Optional)*
**Default:** 100

### BufferMinFreeDiskSpace

**Description:** Min free disk space: The minimum amount of free disk space required to write a batch to disk, if the free disk space is below this value, the sink will not write batches to disk and will drop batches instead. *(Optional)*
**Default:** 2GB

### BufferMaxDiskSpace

**Description:** Max disk space: The maximum amount of disk space to use for the buffer, if the maximum is reached, the sink will drop batches instead of writing them to disk. *(Optional)*
**Default:** 0MB

### BufferCompressionLevel

**Description:** The gzip compression level used for buffer files on disk. *(Optional)*
**Default:** -1, which is gzip's own default compression

### BufferEnableDiskQueue

**Description:** Enable disk queue: If enabled batches will be written to disk when the maximum amount of batches in memory is reached or the application is stopped. *(Optional)*
**Default:** enabled

## Generic MQTT

### MqttURL

**Description:** Enter the URL of the MQTT broker to connect to

### ClientCertificateFile

**Description:** *Enter the client certificate file location if applicable*

### ClientKeyFile

**Description:** *Enter the client key file location if applicable*

### Username

**Description:** Enter the username

### Password

**Description:** Enter the password

### QOS

**Description:** Enter the QOS with which to publish
**Default:** 1 

### KeepAliveSecs

**Description:** Enter the keep alive period(in seconds)
**Default:** 30

### EnableBuffer

**Description:** Optionally enable the buffer, if enabled, the sink will buffer messages when the MQTT broker is not reachable.
**Default:** disabled

### BufferProcessInterval

**Description:** Process interval (in milliseconds): The interval at which the buffer is processed. *(Optional)*
**Default:** 250

### BufferMaxBatchSize

**Description:** The maximum number of messages in a batch, the batch size determines how many messages are sent in one go. *(Optional)*
**Default:** 5000

### BufferMaxBatches

**Description:** The maximum amount of batches to keep in memory, when the maximum is reached a batch will be saved to disk if the disk queue is enabled and there is space available. *(Optional)*
**Default:** 20

### BufferDiskBatches

**Description:** The maximum amount of batches to write to a single file on disk. *(Optional)*
**Default:** 100

### BufferMinFreeDiskSpace

**Description:** The minimum amount of free disk space required to write a batch to disk, if the free disk space is below this value, the sink will not write batches to disk and will drop batches instead. *(Optional)*
**Default:** 2GB

### BufferMaxDiskSpace

**Description:** The maximum amount of disk space to use for the buffer, if the maximum is reached, the sink will drop batches instead of writing them to disk. *(Optional)*
**Default:** 0MB

### BufferCompressionLevel

**Description:** The gzip compression level used for buffer files on disk. *(Optional)*
**Default:** -1, which is gzip's own default compression

### BufferEnableDiskQueue

**Description:** If enabled batches will be written to disk when the maximum amount of batches in memory is reached or the application is stopped. *(Optional)*
**Default:** enabled

Forwarders