curl --request GET \
  --url https://openapi.pluuug.com/v1/contract/category \
  --header 'X-API-Key: <api-key>' \
  --header 'X-Signature: <api-key>'

{
  "next": "<string>",
  "previous": "<string>",
  "results": [
    {
      "id": 123,
      "title": "<string>"
    }
  ]
}