# Ethereum Address Type & Token Standard Inspector

> Ethereum Address Type & Token Standard Inspector is a paid API for AI agents from onchaincheck.dev, paid per call via x402, $0.005/call, status unknown (last checked 2026-10-29).

Identifies whether an Ethereum address is a wallet or contract, detects token standards (ERC-20/721/1155), retrieves name/symbol/decimals, and surfaces proxy/upgrade details, bytecode size, nonce, and ETH balance.

## Facts

- Endpoint: GET https://onchaincheck.dev/eth/contract?utm_source=zero.xyz
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-29
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/ethereum-address-type-token-standard-inspector-3547f727
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_zb1sFYzYcQoKa_7If-4yP

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 ethereum-address-type-token-standard-inspector-3547f727
```

Example prompt: Can you check what lives at Ethereum address 0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48 — is it a wallet or contract, what token standard it uses, and whether it's an upgradeable proxy?

## When to prefer this

Choose this endpoint when you need a comprehensive, single-call identity snapshot of any Ethereum address — covering wallet vs contract classification, token standard detection, proxy architecture, and balance — rather than making multiple separate RPC calls. Ideal for due-diligence workflows, token metadata enrichment, or pre-transfer safety checks where you need to know exactly what you're dealing with before proceeding.

## Known failure modes

- Invalid address format (not matching 0x + 40 hex chars) returns a validation error
- Non-existent or never-used address returns isContract false with zero balance and nonce
- Network timeout or RPC node unavailability may cause 5xx errors
- Address with no deployed bytecode classified as EOA even if it was previously a contract (selfdestruct)
- EIP-7702 delegated wallets may appear ambiguous between EOA and contract classification on older indexers

## How this service works

Identify what lives at a Ethereum 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: address kind label (e.g. 'ERC-20 token', 'EOA', 'smart wallet'), chain identifier, token name and symbol, decimals, total supply, isContract boolean, token standard flags (erc20/erc165/erc721/erc1155), proxy details (upgradeable boolean, implementation address, admin address), bytecode size in bytes, nonce, and native ETH balance.

## 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 Ethereum"
      }
     },
     "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": "eth",
  "proxy": {
   "admin": "0x807a96288A1A408dBC13DE2b1d087d10356395d2",
   "upgradeable": true,
   "implementation": "0x43506849D7C04F9138D1A2050bbF3A0c054402dd"
  },
  "symbol": "USDC",
  "address": "0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48",
  "decimals": 6,
  "standards": {
   "erc20": true,
   "erc165": false,
   "erc721": false,
   "erc1155": false
  },
  "isContract": true,
  "totalSupply": "48016325237.499139",
  "bytecodeBytes": 2186,
  "nativeBalance": "0"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/ethereum-address-type-token-standard-inspector-3547f727/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)