curl --request GET \
  --url https://tonapi.io/v2/nfts/collections/{account_id}

{
  "address": "0:FD595F36B4C1535BEC8461490D38EBB9AE3C38DD6ACE17CA63ABE2C6608BE159",
  "next_item_index": 1,
  "raw_collection_content": "<string>",
  "approved_by": [
    "getgems"
  ],
  "metadata": {},
  "previews": [
    {
      "resolution": "100x100",
      "url": "https://site.com/pic1.jpg"
    }
  ]
}