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Base ERC-721 Owner Lookup
x402
Base ERC-721 Owner Lookup is a paid API for AI agents from api.arysphere.com, paid per call via x402, $0.003/call, status unknown (last checked 2026-10-17).
Returns the current owner address of a specific NFT token ID on the Base blockchain by calling ownerOf() on the ERC-721 contract.
Price / call$0.003
Success—
StatusUnknown
How this service works
ARYSPHERE sells AI-written verdicts on Base token contracts (a grade, a one-liner, a roast and the contract's facts) and Base/Ethereum chain reads, paid per call in USDC on Base over x402 v2. No account and no API key.
Output
A JSON object containing: ok (boolean success flag), chain ('base'), method ('ownerOf'), and a result object with the token's id, the owner wallet address, and the contract token address. Returns the exact on-chain ownerOf() response for the given token ID.
Example use cases
Verify NFT ownership before transfer
“Before I send that NFT, can you confirm who currently owns token ID 101 on the Base contract 0xa990c6a764b73bf43cee5bb40339c3322fb9d55f? I want to make sure it's still in my wallet.”
Gate content by NFT ownership
“Check who owns token ID 7 on Base NFT contract 0xa990c6a764b73bf43cee5bb40339c3322fb9d55f — I need to verify the holder's address before granting them access to the private channel.”
Track NFT after marketplace sale
“I think token ID 888 on Base contract 0xa990c6a764b73bf43cee5bb40339c3322fb9d55f just sold — can you look up who the new owner is right now?”
Technical details
Endpoint
GEThttps://api.arysphere.com/v1/ventures/x402_chain_reads_v1/base_erc721_ownerof?utm_source=zero.xyzWhen to prefer
Choose this endpoint when you need to resolve the current on-chain owner of a specific ERC-721 NFT on the Base L2 network. Prefer this over Ethereum ERC-721 lookups when the NFT collection is deployed on Base (not Ethereum mainnet). Useful for ownership verification, access gating, post-sale tracking, or any workflow where knowing the current holder wallet address is required.
Side effects
- Invalid contract address format (not 0x + 40 hex) returns a 400-level error
- Token ID that does not exist on the contract may return a revert or null owner
- Contract address is not an ERC-721 contract — call will fail or return unexpected data
- Network issues reaching Base RPC may cause timeout or 5xx error
- Token ID provided as non-decimal string may fail validation
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Output
Schema · Response
{
"type": "json",
"example": {
"ok": true,
"chain": "base",
"method": "ownerOf",
"result": {
"id": "5256424",
"owner": "0x456979e89917f4dc1e86662fcdfd4c9766c6684d",
"token": "0xa990c6a764b73bf43cee5bb40339c3322fb9d55f"
},
"service": "x402_chain_reads_v1.base_erc721_ownerof"
}
}Tags
x402
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