curl --request GET \
  --url https://api.privy.io/v1/wallets/{wallet_id}/balance \
  --header 'Authorization: Basic <encoded-value>' \
  --header 'privy-app-id: <privy-app-id>'

{
  "balances": [
    {
      "chain": "base",
      "asset": "eth",
      "raw_value": "1000000000000000000",
      "raw_value_decimals": 18,
      "display_values": {
        "eth": "0.001",
        "usd": "2.56"
      }
    }
  ]
}