curl --request GET \
  --url https://synthesis.trade/api/v1/wallet/{wallet_id}/balance \
  --header 'X-API-KEY: <api-key>'

{
  "success": true,
  "response": [
    {
      "wallet_id": "a1b2c3d4-e5f6-7890-abcd-ef1234567890",
      "chain_id": "POL",
      "address": "0x1234567890abcdef1234567890abcdef12345678",
      "balance": {
        "USDC.e": "1000.000",
        "USDC": "500.000"
      }
    },
    {
      "wallet_id": "a1b2c3d4-e5f6-7890-abcd-ef1234567890",
      "chain_id": "SOL",
      "address": "7xKXtg2CW87d97TXJSDpbD5jBkheTqA83TZRuJosgAsU",
      "balance": {
        "USDC": "250.000"
      }
    }
  ]
}