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	Client	✅	Publish to an external MQTT broker.
broker	Broker	✅	Publish into an embedded broker that serves downstream subscribers.

Schema

• Client - Retry Fields
• Client - Tls Fields
• Client - Dead Letter Fields
• Client Fields
• Broker - Retry Fields
• Broker - Listeners Fields
• Broker Fields
• Client - Protocol Options
• Client - Payload Mode Options
• Broker - Payload Mode Options

Client - 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

Client - 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).

Client - 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).
retain	boolean (bool)		Whether the dead-letter publish should retain the message.

Client 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	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. Examples: 42, 1.2e-10
clean-session	boolean (bool)		Whether to request a clean session on connect.
username	string		Optional username for broker authentication.
password	string		Optional password for broker authentication.
tls	Tls		TLS material for secure connections.
request-channel-capacity	number (integer)		Request channel capacity for the client worker. Examples: 42, 1.2e-10
inflight	number (integer)		Maximum inflight window for QoS1 publishes. Examples: 42, 1.2e-10
qos	number		Publish QoS level (0 or 1).
retain	boolean (bool)		Whether publishes should set the retain flag.
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. Allowed values: auto, json, raw, binary
pool-size	number (integer)		Number of MQTT client connections maintained for parallel publishing. 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	Dead Letter		Dead-letter behaviour when retries are exhausted.

Broker - 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

Broker - Listeners 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).

Broker Fields

Field	Type	Required	Description
retry	Retry		Retry policy applied before surfacing broker publish failures.
qos	number		Publish QoS level (0 or 1).
retain	boolean (bool)		Whether embedded broker publishes should set the retain flag.
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. Allowed values: auto, json, raw, binary
listeners	Listeners[]		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. Examples: 42, 1.2e-10

Client - Protocol Options

Value	Description
v3	V3
v5	V5

Client - Payload Mode Options

Value	Description
auto	Auto
json	Json
raw	Raw
binary	Binary

Broker - Payload Mode Options

Value	Description
auto	Auto
json	Json
raw	Raw
binary	Binary