Chain State

{
  "confidence": 1,
  "data_versions": {
    "abi_packs": "2026-08-03.1",
    "chain": "eip155:8453",
    "denylist": "2026-08-03.1",
    "policy": "2026-09-19",
    "proxy_slots": "7"
  },
  "evidence": [
    {
      "code": "INTERFACE_PROBE_UNANSWERED",
      "detail": "This contract did not answer supportsInterface, so ERC-721 and ERC-1155 support is reported as null. That is not evidence against them: plenty of live contracts predate ERC-165 entirely.",
      "severity": "info",
      "source": "erc165"
    },
    {
      "code": "PROXY_UPGRADEABLE",
      "data": {
        "admin": "0x4fc7850364958d97B4d3f5A08f79db2493f8cA44",
        "implementation": "0x2Ce6311ddAE708829bc0784C967b7d77D19FD779",
        "kind": "zeppelinos"
      },
      "detail": "This is an upgradeable zeppelinos proxy. Everything reported here describes the implementation deployed right now; the admin can point it elsewhere before your next call lands, so this is a risk signal rather than metadata.",
      "severity": "medium",
      "source": "proxy-slots"
    }
  ],
  "ok": true,
  "policy_version": "2026-09-19",
  "request_hash": "sha256:96b41fa639c553a6dc6bfaa1d8ccc056912abc36e8bbde3d65f3e1edc2bd147f",
  "result": {
    "account": {
      "code_size": 1852,
      "detail": "1852 bytes of runtime code",
      "is_contract": true
    },
    "address": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
    "balances": [],
    "chain": "eip155:8453",
    "denylist_hits": [],
    "interfaces": {
      "detail": "supportsInterface did not answer, so ERC-721 and ERC-1155 are reported as unknown rather than absent; ERC-20 is confirmed behaviourally from totalSupply, decimals, and balanceOf",
      "erc1155": null,
      "erc165": null,
      "erc20": true,
      "erc721": null
    },
    "proxy": {
      "address": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
      "admin": "0x4fc7850364958d97B4d3f5A08f79db2493f8cA44",
      "beacon": null,
      "detail": "resolved through the legacy zeppelinos slot; the EIP-1967 slot is empty on this contract, which is the case for Base USDC",
      "implementation": "0x2Ce6311ddAE708829bc0784C967b7d77D19FD779",
      "kind": "zeppelinos",
      "slots_probed": [
        {
          "address": "0x2Ce6311ddAE708829bc0784C967b7d77D19FD779",
          "label": "zeppelinos.implementation",
          "slot": "0x7050c9e0f4ca769c69bd3a8ef740bc37934f8e2c036e5a723fd8ee048ed3f8c3",
          "value": "0x0000000000000000000000002ce6311ddae708829bc0784c967b7d77d19fd779"
        },
        {
          "address": "0x4fc7850364958d97B4d3f5A08f79db2493f8cA44",
          "label": "zeppelinos.admin",
          "slot": "0x10d6a54a4754c8869d6886b5f5d7fbfa5b4522237ea5c60d11bc4e7a1ff9390b",
          "value": "0x0000000000000000000000004fc7850364958d97b4d3f5a08f79db2493f8ca44"
        }
      ],
      "upgradeable": true
    },
    "rpc": {
      "configured": true,
      "endpoints": [],
      "reachable": true
    },
    "token": {
      "decimals": 6,
      "detail": "symbol, decimals, and totalSupply read from the token",
      "symbol": "USDC",
      "total_supply": "4305008625389354"
    },
    "unresolved": [
      "ERC-165 interface support: supportsInterface did not answer"
    ]
  },
  "risk_codes": [
    "PROXY_UPGRADEABLE"
  ],
  "verdict": "warn",
  "warnings": []
}

# bash or zsh: see the payment challenge. Nothing is charged.
curl -sS -g -i -X POST 'https://chainstate.schemasure.com/v1/chain/state' \
  -H 'content-type: application/json' \
  --data-raw '{"address":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913"}'

# x402 v2 sends the challenge base64-encoded in the PAYMENT-REQUIRED header (v1 sends it in the body).
# To read the header:
curl -sS -g -o /dev/null -D - -X POST 'https://chainstate.schemasure.com/v1/chain/state' \
  -H 'content-type: application/json' \
  --data-raw '{"address":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913"}' \
  | grep -i '^payment-required:' | cut -d' ' -f2 | tr -d '\r' | base64 --decode

// npm i @x402/fetch @x402/evm viem
import { wrapFetchWithPayment, x402Client } from "@x402/fetch";
import { registerExactEvmScheme } from "@x402/evm/exact/client";
import { privateKeyToAccount } from "viem/accounts";

// Pays at most $0.02 per call.
const client = new x402Client().setSpendControls({ maxAmountPerPayment: "$0.02" });
registerExactEvmScheme(client, { signer: privateKeyToAccount(process.env.EVM_PRIVATE_KEY) });
const pay = wrapFetchWithPayment(fetch, client);

// Not sure it's safe to pay? ToolVet checks it first for $0.005. Pay for that from a separate
// client: this one is capped at $0.02 per payment. GET https://toolvet.app/api/v1/check?url=https%3A%2F%2Fchainstate.schemasure.com%2Fv1%2Fchain%2Fstate&method=POST
const res = await pay("https://chainstate.schemasure.com/v1/chain/state", {
  method: "POST",
  headers: { "content-type": "application/json" },
  body: JSON.stringify({
    "address": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913"
  }),
});
console.log(res.status, await res.text());

# pip install "x402[requests,evm]"
import os
from eth_account import Account
from x402 import x402ClientSync
from x402.http.clients import x402_requests
from x402.mechanisms.evm import EthAccountSigner
from x402.mechanisms.evm.exact.register import register_exact_evm_client

# Pays at most $0.02 per call.
client = x402ClientSync().set_spend_controls({"max_amount_per_payment": "$0.02"})
register_exact_evm_client(client, EthAccountSigner(Account.from_key(os.environ["EVM_PRIVATE_KEY"])))

with x402_requests(client) as session:
    res = session.post(
        "https://chainstate.schemasure.com/v1/chain/state",
        json={
            "address": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
        },
    )
    print(res.status_code, res.text)