curl --request GET \
  --url https://api.railmail.app/api/v1/topics \
  --header 'X-API-Key: <api-key>'

{
  "data": [
    {
      "topicKey": "APIT-1",
      "name": "Newsletter",
      "description": "Weekly news",
      "status": "ACTIVE",
      "doubleOptInEnabled": true,
      "subscriberCount": 1200,
      "activeSubscriberCount": 1180,
      "createdAt": "2026-06-01T09:00:00Z"
    }
  ],
  "pagination": {
    "page": 0,
    "size": 20,
    "totalElements": 1,
    "totalPages": 1,
    "hasNext": false,
    "hasPrevious": false
  }
}