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JavaScript API

k6/x/mqtt

Client

Client.connect( url, [options] )

Open source

Client.connect()

Establishes a connection to an MQTT broker. When the connection is successfully established, the connect event is triggered.

Signature

client.connect(url, options)

Parameters

Parameter	Type	Description
url	string	Broker URL (for example, `mqtt://broker.emqx.io:1883`)
options	object	Optional connection configuration
options.keepalive	number	Keep-alive interval in seconds (default: 60)
options.connect_timeout	number	Connection timeout in milliseconds (default: 30000)
options.clean_session	boolean	Whether to start with a clean session (default: true)
options.servers	string[]	Array of broker URLs for failover
options.tags	object	Custom tags for metrics (key-value pairs)

Supported broker URL schemas

Schema	Description
`mqtt://`	Plain TCP connection (no encryption)
`mqtts://`	Secure connection over SSL/TLS
`tcp://`	Alias for `mqtt://`
`ssl://`	Alias for `mqtts://`
`tls://`	Alias for `mqtts://`
`ws://`	MQTT over WebSocket
`wss://`	MQTT over secure WebSocket

If the schema is omitted, mqtt:// is used as the default.

SSL/TLS configuration

The extension uses standard k6 TLS configuration for all SSL/TLS settings. Configure certificates, verification, and other TLS-related options using k6’s environment variables and configuration files.