Ethereum NFT owner

$0.01 per call · failed calls are never charged · no account or API key needed

Owner of an NFT on Ethereum: the wallet that holds one ERC-721 token id right now (ownerOf), plus the collection's name and symbol. Use to verify who holds an NFT before a trade, a mint gate or an airdrop; for how many a wallet holds use eth_nft_balance, for the token's metadata eth_nft_metadata. A missing contract is 404, a token that does not exist 422, both uncharged.

Run it free (25 free calls) Buy credits by card (from $5) Example result (JSON)

Try it with your own inputs

0x ERC-721 collection contract address
Token id, a whole number

Uses one of your 25 free calls. Nothing is charged, and a call that fails is not counted.

Inputs

NameTypeDescription
contract (required)string0x ERC-721 collection contract address
tokenId (required)stringToken id, a whole number

Request

Over HTTP, with a card key from /credits:

curl -H "Authorization: Bearer adt_…" "https://agent-data-tools.revmesh2074.workers.dev/eth/nft-owner?contract=0xC36442b4a4522E871399CD717aBDD847Ab11FE88&tokenId=1"

Or one of your 25 free calls, no key:

curl "https://agent-data-tools.revmesh2074.workers.dev/eth/nft-owner?contract=0xC36442b4a4522E871399CD717aBDD847Ab11FE88&tokenId=1&trial=1"

Without a key, the same URL answers 402 Payment Required with x402 and MPP terms, so an agent with a wallet pays per call in USDC (Base, Polygon, Arbitrum or Solana over x402; Base or Tempo over MPP) and retries.

Example result

{
  "chain": "Ethereum",
  "chainId": 1,
  "contract": "0xC36442b4a4522E871399CD717aBDD847Ab11FE88",
  "tokenId": "1",
  "owner": "0x69e67aad5495a48c4ef3f770d93a99935e1dc90d",
  "name": "Uniswap V3 Positions NFT-V1",
  "symbol": "UNI-V3-POS"
}

From an AI agent (MCP)

Add the MCP server to Claude, Cursor or any MCP client. This tool is eth_nft_owner, and the first 25 successful calls are free:

https://agent-data-tools.revmesh2074.workers.dev/mcp

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