Messages (ARCHIVED)

Attentive is a comprehensive personalized mobile messaging solution that can integrate with a variety of different platforms to send mobile messages programmatically. Make calls to the Messages API to send both SMS and MMS promotional and marketing messages to your subscribers. We have various integrations with third-party partners that currently leverage the Messages API. Before you begin, ensure that you're working with a member from our White Glove team ( or an engineer at Attentive to coordinate sending test messages with this API.

Note: Legacy APIs and the APIs outlined in the Attentive API section need separate tokens. Contact for a legacy API token.




Header name Description Value Required
Authorization You must provide an access token. Contact for this token. Bearer <token> Required
Content-type The format of returned data. application/json Required


Parameter Description Example Type Required Notes
to Phone number of a subscriber. 555-555-5555 string Required Currently, Attentive only supports phone numbers from the United States, Canada, and the United Kingdom.
body Body of the SMS/MMS message. 30% off sitewide sale going on now. Use code SAVE30. string Required Attentive automatically prepends the customer’s name to all outgoing messages.

If you want to include a URL, it must be sent with the body.

messageId The unique identifier that is assigned to a campaign message. You need to work with our White Glove team ( or an engineer at Attentive to send test messages to generate a messageId.

This can be used for tracking purposes in Attentive’s platform.

123456789 string Optional
type The type of message. Currently, the only option available is transactional. TRANSACTIONAL string Optional Note that this field is case-sensitive.
mediaUrl URL of image that accompanies MMS.


string Optional Messages sent with a mediaUrl will automatically be converted to MMS.

The following are supported file types:

  • gif
  • png
  • jpg

    Media size must be under 500KB.

Sample JSON request

curl '' \  
-H 'Authorization: Bearer 1a2b3c4d5' \
-H 'Content-Type: application/json' \
-d '{"to": "555-555-5555","body": "30% off sitewide sale going on now. Use code SAVE30.", "messageId": "123456789"}'

Sample JSON response

    "body":"30% off sitewide sale going on now. Use code SAVE30.",

Status codes

The following table lists the returned HTTP status codes.

Code Description Notes
200 Success The message was sent successfully.
400 Bad Request The message was not sent. The following issues could have occurred:
  • Subscriber not found
  • Subscriber is opted-out
  • Invalid Input - phone number or body missing from request
  • Illegal argument passed in
403 Forbidden Invalid API token.
404 Not Found Invalid or unmatched phone number.
500 Internal Server Error Missing required parameters.

Note the following:

  • Messages can only be sent to active and opted-in subscribers.
  • Messages are sent using the shortcode assigned during the onboarding process.