You can register to receive notifications about events through our webhooks system.


Triggered when a contact's address is updated.

Note: This webhook will not be triggered when a contact is added or deleted from the mailing list, nor will it be triggered when an address is changed for a single mailing.

Typical triggers include filling in missing information such as ZIP codes, providing notifications about returned mail, and sending address updates from the National Change of Address database.


The contact ID used by
The contact ID supplied by your application.

Request Body

Content-Type: application/json
{ "contact_id" : "c-17b-4hht", "external_id" : "123456789", "name" : "Joe and Mary Tischler", "old_address" : { "street" : "123 Main St.", "city" : "Lebanon", "state" : "NH", "postal_code" : "03766", "country" : "", "is_deliverable" : true }, "new_address" : { "street" : "123 Main St.", "city" : "Lebanon", "state" : "NH", "postal_code" : "03766", "country" : "", "is_deliverable" : false }, "code" : "returned_mail" "message" : "Letter Returned -- Undeliverable As Addressed", "updated" : "2024-05-20T09:59:33", }

A potential point of confusion involves the is_deliverable field. In the old_address section, it represents our former guess as to whether or not the address was deliverable, before we updated the record. It does not indicate whether or not the old address is currently deliverable.

If we receive a returned letter without a forwarding address, we will send an address update event with the same old and new addresses, but with is_deliverable set to false on the new address, as shown in the example above.

Use the code and message fields to decide how to handle these events in your app. The code field is intended to be consumed by your app, whereas the message field is free-form text intended to be displayed to the end user, which will often be typed by one of our employees.

Reason Codes

In order to allow the list of codes to expand over time, your application MUST treat any unrecognized code as unspecified.

The address was updated without a reason being provided. The accompanying message will typically be blank, but may contain a message, and should be displayed to the end user if present.
The address was updated by an API client.
A letter was returned to us. It may include a forwarding address.