Contract bytecode check

Is this address a contract, and what code does it hold? Returns isContract, deployed bytecode size, and the keccak-256 hash of the bytecode (stable fingerprint for comparing deployments) on Ethereum, Base, Polygon, Arbitrum, or Optimism. Keyless multi-endpoint failover. ?address=0x…&network=base

Input

Example output

{
  "network": "base",
  "address": "0x8335…",
  "isContract": true,
  "bytecodeBytes": 2148,
  "keccak256": "0x…"
}

Try it - see the 402 challenge (free)

curl -i "https://agent402.tools/api/contract-code?address=0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913&network=base"

The response is HTTP 402 Payment Required with exact payment requirements. Any x402 v2 client pays automatically and retries:

Paid call (JavaScript agent)

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

const client = new x402Client();
registerExactEvmScheme(client, { signer: privateKeyToAccount(KEY) });
const payFetch = wrapFetchWithPayment(fetch, client);

const res = await payFetch("https://agent402.tools/api/contract-code?address=0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913&network=base");

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