curl --request GET \
  --url https://panel.sendcloud.sc/api/v2/contracts \
  --header 'Authorization: Basic <encoded-value>'

{
  "next": null,
  "previous": null,
  "contracts": [
    {
      "id": 60,
      "carrier": {
        "code": "lettresuivie",
        "name": "Lettre Suivie"
      },
      "client_id": "sendcloud-1",
      "is_active": true,
      "country": "FR",
      "is_default": true
    },
    {
      "id": 61,
      "carrier": {
        "code": "poste_italiane",
        "name": "Poste Italiane"
      },
      "client_id": "sendcloud-1",
      "is_active": true,
      "country": "IT",
      "is_default": true
    }
  ]
}