kumomta/docs/reference/message/get_meta.md

message:get_meta(KEY)

Messages are associated with some metadata. You can think of this metadata as being equivalent to a JSON object.

The get_meta method allows you to retrieve a field of that object.

msg:set_meta('foo', 'bar')
print(msg:get_meta 'foo') -- prints 'bar'

See also msg:set_meta.

Pre-defined meta values

The following meta values are unique to the message scope:

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Scope	Name	Purpose	Since
Message	queue	specify the name of the queue to which the message will be queued. Must be a string value.
Message	tenant	specify the name/identifier of the tenant, if any. Must be a string value.
Message	campaign	specify the name/identifier of the campaign. Must be a string value.
Message	routing_domain	Overrides the domain of the recipient domain for routing purposes.	{{since('2023.08.22-4d895015', inline=True)}}

!!! Note Additional metadata is available in the message scope that is copied in from the connection scope, for a full list of all available metadata, see the Predefined Metadata page.