MQTT

MQTT (mqtt)

Publish events to external MQTT brokers or an embedded broker instance.

Messaging binary json raw

Minimal example

output:
  mqtt:
    broker: {}
    client:
      endpoint: ""

JSON

{
  "output": {
    "mqtt": {
      "broker": {},
      "client": {
        "endpoint": ""
      }
    }
  }
}

Contents

• Minimal example

• Fields

• Schema

Fields

Field	Type	Required	Description
client	MQTT Client Publisher	✅	Publish to an external MQTT broker.
broker	MQTT Embedded Broker Publisher	✅	Publish into an embedded broker that serves downstream subscribers.

Schema

• MQTT Client Publisher - Retry Fields
• MQTT Client Publisher - MQTT TLS Fields
• MQTT Client Publisher - MQTT Dead Letter Fields
• MQTT Client Publisher Fields
• MQTT Embedded Broker Publisher - Retry Fields
• MQTT Embedded Broker Publisher - Listener Fields
• MQTT Embedded Broker Publisher Fields
• MQTT Client Publisher - MQTT Protocol Options
• MQTT Client Publisher - Payload Mode Options
• MQTT Embedded Broker Publisher - Payload Mode Options

MQTT Client Publisher - Retry Fields

Field	Type	Required	Description
timeout	time-interval (string)	✅	timeout (e.g. 500ms, 2s etc. - default is 30). Examples: 500ms, 2h
retries	number (integer)		number of retries. Examples: 42, 1.2e-10

MQTT Client Publisher - MQTT TLS Fields

Field	Type	Required	Description
ca-certificate	string		Optional CA certificate (PEM encoded).
client-certificate	string		Optional client certificate (PEM encoded).
client-key	string		Optional client private key (PEM encoded).

MQTT Client Publisher - MQTT Dead Letter Fields

Field	Type	Required	Description
topic	string	✅	Topic to publish failed messages to once retries are exhausted.
qos	number		QoS level for dead-letter publishes (0 or 1). Default: 0
retain ✓	boolean (bool)		Whether the dead-letter publish should retain the message. Default: false

MQTT Client Publisher Fields

Field	Type	Required	Description
retry	Retry		Retry policy for publish failures.
endpoint	hostname (string)	✅	Broker endpoint URI (e.g. mqtt://broker:1883 or mqtts://broker:8883). Examples: example.com, localhost
protocol	MQTT Protocol		MQTT protocol version used for publishing. Allowed values: v3, v5
client-id	string		Optional client identifier override.
keep-alive-secs	number (integer)		Keep-alive interval in seconds. Default: 30 Examples: 42, 1.2e-10
clean-session ✓	boolean (bool)		Whether to request a clean session on connect. Default: true
username	string		Optional username for broker authentication.
password	string		Optional password for broker authentication.
tls	MQTT TLS		TLS material for secure connections.
request-channel-capacity	number (integer)		Request channel capacity for the client worker. Default: 10 Examples: 42, 1.2e-10
inflight	number (integer)		Maximum inflight window for QoS1 publishes. Default: 100 Examples: 42, 1.2e-10
qos	number		Publish QoS level (0 or 1). Default: 0
retain ✓	boolean (bool)		Whether publishes should set the retain flag. Default: false
topic	string		Static topic to publish to when dynamic selectors are absent.
topic-field	field (string)		Event field to resolve the topic from at runtime. Examples: data_field
topic-pointer	json-pointer (string)		JSON pointer to resolve the topic from at runtime.
payload-mode	Payload Mode		Controls how event payloads are encoded prior to publish. Default: auto Allowed values: auto, json, raw, binary
pool-size	number (integer)		Number of MQTT client connections maintained for parallel publishing. Default: 1 Examples: 42, 1.2e-10
response-topic	string		Optional response topic for MQTT v5 publishes.
correlation-data	string		Optional correlation data (base64 encoded) for MQTT v5 publishes.
message-expiry-interval-secs	number (integer)		Optional message expiry interval (seconds) for MQTT v5 publishes. Examples: 42, 1.2e-10
dead-letter	MQTT Dead Letter		Dead-letter behaviour when retries are exhausted.

MQTT Embedded Broker Publisher - Retry Fields

Field	Type	Required	Description
timeout	time-interval (string)	✅	timeout (e.g. 500ms, 2s etc. - default is 30). Examples: 500ms, 2h
retries	number (integer)		number of retries. Examples: 42, 1.2e-10

MQTT Embedded Broker Publisher - Listener Fields

Field	Type	Required	Description
bind	hostname (string)	✅	Socket address in host:port form for the embedded broker listener. Examples: example.com, localhost
tls ✓	boolean (bool)		Whether TLS should be enabled for this listener (placeholder). Default: false

MQTT Embedded Broker Publisher Fields

Field	Type	Required	Description
retry	Retry		Retry policy applied before surfacing broker publish failures.
qos	number		Publish QoS level (0 or 1). Default: 0
retain ✓	boolean (bool)		Whether embedded broker publishes should set the retain flag. Default: false
topic	string		Static topic used when dynamic selectors are absent.
topic-field	field (string)		Event field to resolve the topic from. Examples: data_field
topic-pointer	json-pointer (string)		JSON pointer to resolve the topic from.
payload-mode	Payload Mode		Controls how payloads are encoded prior to publish. Default: auto Allowed values: auto, json, raw, binary
listeners	Listener[]		Listener surfaces to bind for the embedded broker.
persistence-path	string		Optional on-disk directory for broker persistence (defaults to job data dir).
topic-prefix	string		Optional prefix applied to topics before publishing into the embedded broker.
worker-threads	number (integer)		Number of worker threads dedicated to the embedded broker runtime. Default: 1 Examples: 42, 1.2e-10

MQTT Client Publisher - MQTT Protocol Options

Value	Name	Description
v3	v3	V3
v5	v5	V5

MQTT Client Publisher - Payload Mode Options

Value	Name	Description
auto	auto	Auto
json	json	Json
raw	raw	Raw
binary	binary	Binary

MQTT Embedded Broker Publisher - Payload Mode Options

Value	Name	Description
auto	auto	Auto
json	json	Json
raw	raw	Raw
binary	binary	Binary