Who owns this NFT?
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.
Answeringour last check, 2026-09-24
1 of 1checks answered this week
925 msmedian answer time
$0.002listed price per call
$0.002price it asked us
Paid test badge: not yet. The checks above are free: we call the tool without paying and read the payment request it sends back. The Verified badge needs paid calls whose answers match the promised output, and nobody can buy a badge.
Endpoint
GET https://agent402.tools/api/erc721-owner
| Category | Market data |
|---|---|
| Provider host | agent402.tools |
| Networks | algorand:wGHE2Pwdvd7S12BL5FaOP20EGYesN73ktiC1qzkkit8=, eip155:10, eip155:1329, eip155:137, eip155:143, eip155:42161, eip155:42220, eip155:43114, eip155:4663, eip155:8453, solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp, stellar:pubnet |
| Payment schemes | exact, upto |
| Self-reported calls, 30 days | 5 from 1 payers (the provider's figure, not ours) |
Our checks, last 30 days
| Day | Result | HTTP | Asked | Time |
|---|---|---|---|---|
| 2026-09-24 | valid payment request | 402 | $0.002 | 925 ms |
Example input (from the provider)
{
"method": "GET",
"queryParams": {
"contract": "0x57f1887a8BF19b14fC0dF6Fd9B2acc9Af147eA85",
"network": "ethereum",
"tokenId": "0xaf2caa1c2ca1d027f1ac823b529d0a67cd144264b2789fa2ea4d63a67c7103cc"
},
"type": "http"
}
Promised output schema (from the provider)
{
"$schema": "https://json-schema.org/draft/2020-12/schema",
"properties": {
"input": {
"additionalProperties": false,
"properties": {
"method": {
"enum": [
"GET"
],
"type": "string"
},
"queryParams": {
"properties": {
"contract": {
"description": "ERC-721 contract address (0x\u2026).",
"type": "string"
},
"network": {
"description": "ethereum / base / polygon / arbitrum / optimism (default base).",
"type": "string"
},
"tokenId": {
"description": "Token id - decimal or 0x hex string.",
"type": "string"
}
},
"required": [
"contract",
"tokenId"
],
"type": "object"
},
"type": {
"const": "http",
"type": "string"
}
},
"required": [
"type",
"method"
],
"type": "object"
},
"output": {
"properties": {
"example": {
"properties": {
"contract": {
"type": "string"
},
"network": {
"type": "string"
},
"owner": {
"type": "string"
},
"tokenId": {
"type": "string"
}
},
"required": [
"network",
"contract",
"tokenId",
"owner"
],
"type": "object"
},
"type": {
"type": "string"
}
},
"required": [
"type"
],
"type": "object"
}
},
"required": [
"input"
],
"type": "object"
}