# x402node Contract Verification Checker

> x402node Contract Verification Checker is a paid API for AI agents from api.x402node.dev, paid per call via x402, $0.005/call, status unknown (last checked 2026-09-14).

Checks whether a smart contract's source code is verified on a block explorer, returning contract name, compiler version, and proxy status across major EVM chains.

## Facts

- Endpoint: GET https://api.x402node.dev/chain/contract-verify
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402node-contract-verification-checker-d855095d
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_2cSmDJgNTV8R8JeFninPR

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 x402node-contract-verification-checker-d855095d
```

Example prompt: Before I interact with this contract at 0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48 on Ethereum, can you check if its source code is verified on the block explorer and tell me the contract name, compiler, and whether it's a proxy?

## When to prefer this

Use this endpoint when an AI agent needs a quick, programmatic pre-interaction safety check on a smart contract — especially before approving transactions, interacting with DeFi protocols, or assessing whether a token contract is legitimate. It covers the most popular EVM chains (Ethereum, Base, Arbitrum, Optimism, Polygon, BSC) in a single call, which LLMs cannot do live on their own.

## Known failure modes

- Invalid or malformed contract address returns an error
- Unsupported chain name returns an error or empty result
- Contract exists but source is not verified — returns unverified status
- Network timeout reaching the block explorer API
- Contract address not found on the specified chain

## How this service works

Check whether a smart contract's source code is verified on the block explorer, with contract name, compiler and proxy status across Ethereum/Base/Arbitrum/Optimism/Polygon/BSC - a pre-interaction safety check agents need that LLMs cannot perform live. contract verified, source code verified, contract audit, unverified contract, contract safety, is contract safe Accepts payment on Base or Solana — either network works.

## Output

Returns whether the contract's source code is verified, the contract name, the Solidity compiler version used, proxy status (e.g. whether it's an upgradeable proxy), and the chain it was checked on. Useful as a pre-interaction safety signal.

## Example request

```json
{
 "chain": "ethereum",
 "address": "0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48"
}
```

## 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": {
      "chain": {
       "type": "string",
       "description": "ethereum, base (default), arbitrum, optimism, polygon, bsc"
      },
      "address": {
       "type": "string",
       "description": "Contract address (required)"
      }
     }
    }
   },
   "additionalProperties": false
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402node-contract-verification-checker-d855095d/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.x402node.dev](https://www.zero.xyz/host/api.x402node.dev/llms.txt)