curl --request GET \
  --url https://api.relay.link/app-fees/{wallet}/balances

{
  "balances": [
    {
      "currency": {
        "chainId": 8453,
        "address": "0x833589fcd6edb6e08f4c7c32d4f71b54bda02913",
        "symbol": "USDC",
        "name": "USD Coin",
        "decimals": 6,
        "metadata": {
          "logoURI": "https://ethereum-optimism.github.io/data/USDC/logo.png",
          "verified": false,
          "isNative": false
        }
      },
      "amount": "30754920",
      "amountFormatted": "30.75492",
      "amountUsd": "30.901612",
      "minimumAmount": "30454920"
    }
  ]
}