# Verified Contract Metadata Lookup

> Verified Contract Metadata Lookup is a paid API for AI agents from api.x402node.dev, paid per call via x402, $0.015/call, status unknown (last checked 2026-09-16).

Returns verified contract metadata (name, compiler version, optimization, license, proxy/implementation address) for a smart contract by address and chain, sourced from a block explorer.

## Facts

- Endpoint: GET https://api.x402node.dev/contract/source
- Price: $0.015/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-16
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/verified-contract-metadata-lookup-8e523e85
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_tZo-278dQFIyuMeaGfBkK

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 verified-contract-metadata-lookup-8e523e85
```

Example prompt: Can you look up the verified contract metadata for address 0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48 on Ethereum mainnet — I want to know the contract name, compiler version, whether it uses a proxy, and what the implementation address is?

## When to prefer this

Use this endpoint when you need quick, structured contract metadata (name, compiler, license, proxy info) without the overhead of fetching full source code. Ideal for auditing pipelines, contract identity resolution, proxy detection, and compliance checks where only build metadata is required. Prefer this over full source endpoints when bandwidth or cost is a concern.

## Known failure modes

- Contract address not verified on the target block explorer — returns error or empty metadata
- Unsupported chain ID — returns an error indicating the chain is not available
- Invalid contract address format — returns a validation error
- Block explorer API key rate limit or downtime — returns a service unavailable error
- Contract exists on-chain but has no verified metadata — returns partial or null fields

## How this service works

Verified contract metadata by address and chain: contract name, compiler version, optimization, license, and proxy with implementation address, from a block explorer behind an API key. Does not return full source. contract source, verified contract, compiler version, proxy implementation, contract metadata Accepts payment on Base or Solana — either network works.

## Output

Returns a JSON object containing the contract name, Solidity compiler version, optimization enabled/disabled status, SPDX license identifier, whether the contract is a proxy, and the implementation contract address if applicable. Does not include full source code.

## 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": "default ethereum"
      },
      "address": {
       "type": "string",
       "description": "contract 0x..."
      }
     }
    }
   },
   "additionalProperties": false
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/verified-contract-metadata-lookup-8e523e85/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)