# ERC721 Token Metadata URI Lookup

> ERC721 Token Metadata URI Lookup is a paid API for AI agents from twin.unykorn.org, paid per call via x402, $0.003/call, status unknown (last checked 2026-09-29).

Returns the metadata URI for a specific ERC721 NFT token by contract address and token ID on supported EVM chains

## Facts

- Endpoint: POST https://twin.unykorn.org/erc721-token-uri?utm_source=zero.xyz
- Price: $0.003/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-29
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/erc721-token-metadata-uri-lookup-c2c41f5d
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_BOvsAW3azQ99tJH5NRV86

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 erc721-token-metadata-uri-lookup-c2c41f5d -d '<json body>'
```

Example prompt: What is the metadata URI for token ID 1337 of the ERC721 contract 0xBC4CA0EdA7647A8aB7C2061c2E118A18a936f13D on Ethereum?

## When to prefer this

Use this endpoint when you need the raw tokenURI from an ERC721 contract on any of the ten supported EVM chains and want a paid, reliable API call with a receipt — especially when you don't have direct RPC access or want a chain-abstracted, multi-network solution without managing your own node connections.

## Known failure modes

- Invalid contract address format (must be 0x-prefixed 40-hex address)
- Token ID does not exist on the specified contract
- Contract is not an ERC721 contract or does not implement tokenURI
- Chain not in supported list (ethereum, base, polygon, arbitrum, optimism, bsc, avalanche, gnosis, linea, scroll)
- RPC node unavailability or timeout for the requested chain
- Payment failure or insufficient x402 funds

## How this service works

Metadata URI for one ERC721 token — Genesis402 / UnyKorn Operator Network

## Output

Returns a JSON object containing ok status, the type field 'erc721-token-uri', a payment receipt with transaction hash, USD amount, and receipt ID, plus a generated_at ISO 8601 timestamp. The core output is the token URI string pointing to the NFT's metadata (typically an IPFS or HTTPS URL).

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "params": {
   "type": "object",
   "properties": {
    "chain": {
     "enum": [
      "ethereum",
      "base",
      "polygon",
      "arbitrum",
      "optimism",
      "bsc",
      "avalanche",
      "gnosis",
      "linea",
      "scroll"
     ],
     "type": "string"
    },
    "tokenId": {
     "type": "integer",
     "minimum": 0
    },
    "contract": {
     "type": "string",
     "pattern": "^0x[0-9a-fA-F]{40}$"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "ok": true,
  "type": "erc721-token-uri",
  "receipt": {
   "tx_hash": "0x<64hex>",
   "amount_usd": 0.25,
   "receipt_id": "g402-<16hex>"
  },
  "generated_at": "<iso8601>"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/erc721-token-metadata-uri-lookup-c2c41f5d/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from twin.unykorn.org](https://www.zero.xyz/host/twin.unykorn.org/llms.txt)