# Multichain RPC – ERC-721 NFT Metadata Lookup

> Multichain RPC – ERC-721 NFT Metadata Lookup is a paid API for AI agents from multichain-rpc.clankerceo.workers.dev, paid per call via x402, $0.004/call, status unknown (last checked 2026-09-15).

Fetches on-chain ERC-721 NFT metadata (name, token URI, standard) for a given contract address and token ID on EVM chains including Base, Polygon, Arbitrum, Optimism, and Ethereum.

## Facts

- Endpoint: GET https://multichain-rpc.clankerceo.workers.dev/erc721-metadata
- Price: $0.004/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/multichain-rpc-erc-721-nft-metadata-lookup-7d803545
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_BLwYnKl_kUT-PavAWjCrr

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 multichain-rpc-erc-721-nft-metadata-lookup-7d803545
```

Example prompt: What's the metadata for token ID 1 of the ERC-721 contract 0xBC4CA0EdA7647A8aB7C2061c2E118A18a936f13D on Ethereum — give me the name, token URI, and any on-chain metadata?

## When to prefer this

Choose this endpoint when you need cheap, pay-per-call ERC-721 metadata lookups across multiple EVM chains (Base, Polygon, Arbitrum, Optimism, Ethereum) without managing your own RPC infrastructure. It is ideal for AI agents that need factual, on-chain NFT data priced in USDC via x402 micropayments, avoiding subscription overhead for low-volume or bursty queries.

## Known failure modes

- Invalid or non-existent contract address returns an error or empty metadata
- Token ID not minted yet may return a revert or null metadata
- Unsupported chain name returns a bad request error
- IPFS or HTTP token URI that is unreachable may result in partial metadata
- Malformed contract address format causes a query failure
- Rate limits or RPC node downtime may cause transient errors

## How this service works

Cheap, factual EVM chain lookups priced per call in USDC. Base, Polygon, Arbitrum, Optimism and Ethereum.

## Output

A JSON object containing the chain name, contract address, token ID, NFT standard (erc721), the raw token URI (e.g. ipfs://…), and the resolved metadata object (including the NFT name and any other on-chain fields).

## 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",
    "queryParams"
   ],
   "properties": {
    "type": {
     "enum": [
      "http"
     ],
     "type": "string"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "properties": {
      "chain": {
       "type": "string"
      },
      "contract": {
       "type": "string"
      },
      "token_id": {
       "type": "string"
      }
     }
    }
   }
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "enum": [
      "json"
     ],
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "chain": "base",
  "contract": "0x…",
  "metadata": {
   "name": "Item #1"
  },
  "standard": "erc721",
  "token_id": "1",
  "token_uri": "ipfs://…"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/multichain-rpc-erc-721-nft-metadata-lookup-7d803545/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from multichain-rpc.clankerceo.workers.dev](https://www.zero.xyz/host/multichain-rpc.clankerceo.workers.dev/llms.txt)