Create a custom field

POST

/api/custom-fields

Define a new custom field. Use the returned mergeTag in an email subject or body.

Request

Body Params application/jsonRequired

Examples

Responses

🟢201

application/json

Custom field created

Bodyapplication/json

🟠409

🟠400ValidationError

🟠401Unauthorized

🟠403EmailNotVerified

Request Example

Shell

JavaScript

Java

Swift

cURL

Key derived from the labelExplicit key and data type

curl --location 'https://api.maildesk.io/api/custom-fields' \
--header 'Content-Type: application/json' \
--data '{
    "label": "Latest Destination"
}'

Response Example

201 - Success

{
    "customField": {
        "id": "01JA2Z3NDEKTSV4RRFFQ69G5FA",
        "key": "latest_destination",
        "label": "Latest Destination",
        "dataType": "text",
        "mergeTag": "{{customFields.latest_destination}}",
        "createdAt": "2026-10-07T10:00:00.000Z",
        "updatedAt": "2026-10-07T10:00:00.000Z"
    }
}

Modified at 2026-10-08 06:32:45

List custom fields

Update a custom field