Update a custom field

PUT

/api/custom-fields/{id}

Change the label or data type. The key cannot be changed, so existing merge
tags keep working. Values already stored on subscribers are not converted.

Request

Path Params

Body Params application/jsonRequired

Examples

Responses

🟢200

application/json

Custom field updated

Bodyapplication/json

🟠400ValidationError

🟠401Unauthorized

🟠403EmailNotVerified

🟠404CustomFieldNotFound

Request Example

Shell

JavaScript

Java

Swift

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

Response Example

200 - Success

{
    "customField": {
        "id": "01JA2Z3NDEKTSV4RRFFQ69G5FA",
        "key": "latest_destination",
        "label": "Last Trip Destination",
        "dataType": "text",
        "mergeTag": "{{customFields.latest_destination}}",
        "createdAt": "2026-10-07T10:00:00.000Z",
        "updatedAt": "2026-10-07T11:30:00.000Z"
    }
}

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

Create a custom field

Delete a custom field