curl --request GET \
  --url https://app.formbricks.com/api/v2/management/contact-attribute-keys \
  --header 'x-api-key: <api-key>'

{
  "data": [
    {
      "id": "<string>",
      "createdAt": "2021-01-01T00:00:00.000Z",
      "updatedAt": "2021-01-01T00:00:00.000Z",
      "isUnique": false,
      "key": "email",
      "name": "Email Address",
      "description": "The user's email address",
      "type": "custom",
      "workspaceId": "<string>",
      "environmentId": "<string>"
    }
  ],
  "meta": {
    "total": 123,
    "limit": 123,
    "offset": 123
  }
}