NFT owner lookup (ERC-721
Who owns this NFT? Calls ownerOf(tokenId) on any ERC-721 contract on Ethereum, Base, Polygon, Arbitrum, or Optimism. Complements nft-holdings (which lists a WALLET's NFTs) - this answers by TOKEN. Keyless multi-endpoint failover.
Go to this service →Our latest check (2026-10-11)
- Answering
- Yes — valid x402 payment terms
- Time to answer
- 196 ms
- Price
- $0.002 per call
- Paying buyers, last 30 days
- 3 (directory's own records)
- Paid calls, last 30 days
- 3
- Category
- Blockchain reads
- Address
- https://agent402.tools/api/erc721-owner
Accuracy
Accuracy scores are published once a seller has enough paid checks against an independent record (at least 7 scored answers over at least 7 days). Until then no score is shown, and a missing score is never a pass.
For agents
This page as JSON: /sellers/41ee52c77f45.json. Paid lookup by address: GET /api/seller?resource=… ($0.001, x402).