Custom Subscriber Attributes

Learn how to create Custom Subscriber Attributes to store additional data fields for your subscribers.

Subscriber data is stored with predefined subscriber attributes such as First Name, Last Name, Email, etc. You can create your own fields to store any additional types of data for your subscribers. These Custom Subscriber Attributes can help you organize subscribers to create send lists, build groups, and more.

You can add/update/delete your account's Custom Subscriber Attributes in the platform dashboard or with the Mobile Text Alerts API Custom Fields endpoints.

The image below shows how custom attributes appear in the platform dashboard. See Manage Custom Subscriber Attributes in the Dashboard to learn more.

Manage Custom Subscriber Attributes with the API

In the Mobile Text Alerts API, all endpoints for Custom Subscriber Attributes are located under /custom-fields. Custom Fields is the previous name for what is now called Custom Subscriber Attributes.

Available API actions:

• Create a new Custom Subscriber Attribute

• List all Custom Subscriber Attributes

• Update a Custom Subscriber Attribute

• Delete a Custom Subscriber Attribute

• Get a Custom Subscriber Attribute

Create a new Custom Subscriber Attribute

A new Custom Subscriber Attribute can be created for your account by calling the POST /custom-fields endpoint.

Request Body

Name	Type	Description
name	string	The name of the attribute.
type	string enum	The data type of the attribute, one of the following: string number date (the date format must be specified in the format field) boolean (used for check boxes) select (you will need to list the options in the options[] field) address multi-select (you will need to list the options in the options[] field)
options[]	string[]	For select or multi-select , the list of possible string values are listed here.
format	string enum	Determines the format of the date . One of the following: Month D, YYYY , MM/DD/YYYY, DD/MM/YYYY

List all Custom Subscriber Attributes

See all Custom Subscriber Attributes that have been created on your account by calling the GET /custom-fields endpoint.

This endpoint returns an id field for each attribute. Use it as the customFieldId in other requests to /custom-fields endpoints.

Rate Limit

This endpoint overrides the general rate limit with an account rate limit. Requests are limited by the authenticated account instead of the IP address. This endpoint is limited to 15 requests per 15 seconds.

Example Request

curl --location 'https://api.mobile-text-alerts.com/v3/custom-fields' \
  --header 'Authorization: Bearer 6078eebf-7661-5458-330e-74cd055a0b08'

Update a Custom Subscriber Attribute

You can make changes to existing Custom Subscriber Attributes that have been created on your account by calling the PATCH /custom-fields/{customFieldId} endpoint with the identifying {customFieldId} of the attribute to be updated as a path parameter.

Request Body

Name	Type	Description
name	string	The name of the attribute.
type	string enum	The data type of the attribute, one of the following: string number date (the date format must be specified in the format field) boolean (used for check boxes) select (you will need to list the options in the options[] field) address multi-select (you will need to list the options in the options[] field)
options[]	string[]	For select or multi-select , the list of possible string values are listed here.
format	string enum	Determines the format of the date . One of the following: Month D, YYYY , MM/DD/YYYY, DD/MM/YYYY

Example Request

In the below example, update customFieldId: 7769 with a new name.

curl -L \
  --request PATCH \
  --url 'https://api.mobile-text-alerts.com/v3/custom-fields/7769' \
  --header 'Authorization: Bearer 3098eebf-7661-5858-890e-65cd054a0b03' \
  --header 'Content-Type: application/json' \
  --data '{
    "name": "New Name"
  }'

Delete a Custom Subscriber Attribute

Custom Subscriber Attributes can be deleted by calling the DELETE /custom-fields/{customFieldId} endpoint. This request does not require a request body. Simply include the {customFieldId} of the attribute to be deleted as a path parameter with your request.

Example Request

In the below example, deleting attribute with id: 7769:

curl --request DELETE --location 'https://api.mobile-text-alerts.com/v3/custom-fields/7769' \
  --header 'Authorization: Bearer 3098eebf-7661-5858-890e-65cd054a0b03'

Get a Custom Subscriber Attribute

List data for a specific Custom Subscriber Attribute with the GET /custom-fields/{customFieldId} endpoint. Include the {customFieldId} of the attribute to be retrieved as a path parameter.

Example Request

curl --location 'https://api.mobile-text-alerts.com/v3/custom-fields/7769' \
  --header 'Authorization: Bearer 3098eebf-7661-5858-890e-65cd054a0b03'

Example Response (for a date type attribute)

{
  "data": {
    "id": 7769,
    "accountId": 1195226,
    "name": "Birthday",
    "type": "date",
    "options": [],
    "format": "MM/DD/YYYY",
    "created": "2025-07-17T20:51:34.000Z"
  }
}

Use Custom Subscriber Attributes

Once you have created Custom Subscriber Attributes on your account, you can start adding custom data to your subscribers. See Assign Custom Subscriber Attributes to learn how to add and edit these attributes for your individual subscribers.

After you have these attributes assigned to your subscribers, you can use Custom Subscriber Attributes as a condition attribute for your Adaptive Groups.