POST /messaging/v1/email/messages/

Sends a message to multiple recipients using a send definition. You can provide a messageKey in the request; otherwise, the messageKey is automatically generated in the response. The limit is 2000 recipients per request. If you send attributes with the recipients, we recommend no more than 500 recipients per request.

Name	Type		Description
definitionKey	string	Required	Unique identifier of the definition.
recipients	array	Required	Array of recipient objects that contain parameters and metadata for the recipients, such as send tracking and personalization attributes. Use this parameter to send to multiple recipients in one request. Use either the recipient or recipients parameter, but not both.
recipients.contactKey	string	Required	Unique identifier for a subscriber in Marketing Cloud. Each request must include a contactKey. You can use an existing subscriber key or create one at send time by using the recipient’s email address.
recipients.to	string		Channel address of the recipient. For email, it’s the recipient's email address.
recipients.messageKey	string		Unique identifier used to track message status. Can be automatically created when you create a message or provided as part of the request. Can be up to 100 characters, and there are no restricted characters. Each recipient in a request must have a unique messageKey. If you use a duplicate messageKey in the same send request, the message is rejected.
recipients.attributes	object		Information used to personalize the message for the recipient. Written as key pairs. The attributes match profile attributes, content attributes, or triggered send data extension attributes.
attributes	object		Information used to personalize the message for the request. Written as key pairs. The attributes match profile attributes, content attributes, or triggered send data extension attributes.

Status	Name	Type	Description
202			Request is accepted. Review example response.
	requestId	string	The unique identifier of this request.
	errorcode	string	Error code for the exception
	messageKey	string	Unique identifier to track message send status.

Response	Reason
202 Accepted	Request is accepted. Review example response.
400 Bad Request	Invalid request
403 Forbidden	Failed to pass authorization.
500 Server Error	Internal error