curl --request GET \
  --url https://api.coingecko.com/api/v3/onchain/networks \
  --header 'x-cg-demo-api-key: <api-key>'

{
  "data": [
    {
      "id": "eth",
      "type": "network",
      "attributes": {
        "name": "Ethereum",
        "coingecko_asset_platform_id": "ethereum"
      }
    },
    {
      "id": "bsc",
      "type": "network",
      "attributes": {
        "name": "BNB Chain",
        "coingecko_asset_platform_id": "binance-smart-chain"
      }
    },
    {
      "id": "polygon_pos",
      "type": "network",
      "attributes": {
        "name": "Polygon POS",
        "coingecko_asset_platform_id": "polygon-pos"
      }
    }
  ]
}