# ERC-721 Token Lookup by Owner

> ERC-721 Token Lookup by Owner is a paid API for AI agents from anibalb.duckdns.org, paid per call via x402, $0.002/call, status unknown (last checked 2026-10-31).

Returns all ERC-721 NFT tokens held by a given wallet address on a specified contract, including token IDs and URIs.

## Facts

- Endpoint: GET https://anibalb.duckdns.org/x402/erc721-tokens?utm_source=zero.xyz
- Price: $0.002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-31
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/erc-721-token-lookup-by-owner-3ebd45bc
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_ddKZRbo8_0P11n4dVDqke

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 erc-721-token-lookup-by-owner-3ebd45bc
```

Example prompt: Can you look up all the ERC-721 NFTs owned by wallet address 0xAbC...123 on the Bored Ape Yacht Club contract and show me each token ID and its metadata URI?

## When to prefer this

Use this endpoint when you need a quick, no-account onchain lookup of ERC-721 token holdings for a specific wallet, especially in a pay-per-call context where you don't want to maintain API keys or subscriptions. Prefer it over indexers like Alchemy/Moralis NFT APIs when minimizing setup overhead and paying micro-amounts per call via x402 USDC is acceptable. Best for spot checks, ownership verification, or lightweight NFT portfolio reads.

## Known failure modes

- Invalid or checksumless wallet address returns an error or empty result
- Contract address not an ERC-721 contract returns empty or error
- Rate limiting or payment failure (x402 USDC payment not accepted) returns 402
- Network/RPC timeout if the blockchain node is unreachable
- Wallet holds zero tokens — returns count:0 and empty tokens array

## How this service works

Public data and utility APIs paid per call in USDC on Base (x402). No accounts, no API keys. 174 routes: crypto/equity data, onchain reads, DNS/email/security intel, geo/weather, x402 payment diagnostics, dev utilities and more.

## Output

A JSON object containing the owner address, a count of tokens held, and an array of token objects each with a token_id and token_uri (e.g. an IPFS link to metadata).

## 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",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "properties": {}
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "count": 2,
  "owner": "0x...",
  "tokens": [
   {
    "token_id": "1",
    "token_uri": "ipfs://..."
   }
  ]
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/erc-721-token-lookup-by-owner-3ebd45bc/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from anibalb.duckdns.org](https://www.zero.xyz/host/anibalb.duckdns.org/llms.txt)