# OP Mainnet Onchain Data – Address Inspector

> OP Mainnet Onchain Data – Address Inspector is a paid API for AI agents from onchaincheck.dev, paid per call via x402, $0.005/call, status unknown (last checked 2026-10-30).

Returns the full onchain profile of any OP Mainnet address: EOA vs contract, token standard, name/symbol, proxy implementation, bytecode size, nonce, and ETH balance.

## Facts

- Endpoint: GET https://onchaincheck.dev/optimism/contract?utm_source=zero.xyz
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-30
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/op-mainnet-onchain-data-address-inspector-03a1e994
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_mQNV_rz0Ti5dj1vtBhlgq

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability op-mainnet-onchain-data-address-inspector-03a1e994
```

Example prompt: What is the address 0x0b2C639c533813f4Aa9D7837CAf62653d097Ff85 on OP Mainnet — is it a wallet or contract, and if it's a token tell me its name, symbol, decimals, and whether it's an upgradeable proxy?

## When to prefer this

Use this endpoint when you need a comprehensive onchain profile of an OP Mainnet address in a single call — especially when you need to distinguish EOA from contract, detect proxy patterns, or retrieve token metadata. Prefer it over chain explorers when you need structured JSON output suitable for automated agent workflows on Optimism specifically (not Ethereum mainnet, Base, or Arbitrum).

## Known failure modes

- Invalid or malformed address (not a valid 0x 40-hex-char string) returns a 400 error
- Address not found or zero activity on OP Mainnet may return minimal fields
- RPC timeout or OP Mainnet node unavailability causes 503 or timeout
- Payment not included or insufficient USDC triggers x402 payment required response

## How this service works

Identify what lives at a OP Mainnet address: wallet (EOA, including EIP-7702 delegation) or contract, which token standard it implements (ERC-20, ERC-721, ERC-1155), name and symbol, upgradeable-proxy implementation and admin, smart-wallet proxies, bytecode size, nonce and ETH balance.

## Output

A JSON object containing: the classified kind of the address (e.g. 'ERC-20 token', 'EOA', 'contract'), token name and symbol, decimals and total supply if applicable, proxy metadata (upgradeable flag, implementation address, admin address), supported token standards (erc20/erc721/erc1155/erc165 booleans), bytecode size in bytes, nonce, and native ETH balance — all scoped to OP Mainnet.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "address"
     ],
     "properties": {
      "address": {
       "type": "string",
       "pattern": "^0x[0-9a-fA-F]{40}$",
       "description": "Any address on OP Mainnet"
      }
     },
     "additionalProperties": false
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "kind": "ERC-20 token",
  "name": "USD Coin",
  "chain": "optimism",
  "proxy": {
   "admin": "0xbB8a939e2B1923d248AC4c2f6aEd0a4D71CB18A3",
   "upgradeable": true,
   "implementation": "0xdEd3b9a8DBeDC2F9CB725B55d0E686A81E6d06dC"
  },
  "symbol": "USDC",
  "address": "0x0b2C639c533813f4Aa9D7837CAf62653d097Ff85",
  "decimals": 6,
  "standards": {
   "erc20": true,
   "erc165": false,
   "erc721": false,
   "erc1155": false
  },
  "isContract": true,
  "totalSupply": "141636562.037185",
  "bytecodeBytes": 1852,
  "nativeBalance": "0"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/op-mainnet-onchain-data-address-inspector-03a1e994/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from onchaincheck.dev](https://www.zero.xyz/host/onchaincheck.dev/llms.txt)