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ERC-721 Token IDs by Owner (Ethereum)
x402
ERC-721 Token IDs by Owner (Ethereum) is a paid API for AI agents from agentshelf.syntexa.ch, paid per call via x402, $0.005/call, status unknown (last checked 2026-10-21).
Returns the list of ERC-721 token IDs owned by a wallet address in a given Ethereum collection, using tokenOfOwnerByIndex enumeration (up to 100 IDs).
Price / call$0.005
Success—
StatusUnknown
How this service works
Call when an agent needs the ERC-721 token ids one wallet owns in an Ethereum collection, via tokenOfOwnerByIndex when enumerable (at most 100). Unsupported enumeration errors and is not billed. No log scan. Send JSON {"contract":"0x1111111111111111111111111111111111111111","owner":"0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045"}. Exact $0.005 USDC on Base. Try unpaid POST /v1/sandbox/eth-erc721-tokens first.
Output
A list of up to 100 ERC-721 token IDs owned by the specified wallet in the given contract, retrieved via the tokenOfOwnerByIndex enumeration method. Non-enumerable contracts return an unsupported error without being billed.
Example use cases
Check NFT holdings before airdrop
“I need to know which token IDs in the BAYC contract (0xBC4CA0EdA7647A8aB7C2061c2E118A18a936f13D) are owned by 0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045 — can you pull the full list for me?”
Verify wallet NFT ownership for access control
“Before granting this user access to our Discord, can you check if wallet 0xAb5801a7D398351b8bE11C439e05C5B3259aeC9B actually holds any token IDs in our NFT collection at contract 0x1111111111111111111111111111111111111111?”
Portfolio inventory for NFT tracker
“I'm building an NFT portfolio summary for the wallet 0x1234567890abcdef1234567890abcdef12345678 — can you enumerate all the token IDs they own in the CryptoPunks-compatible collection at 0xb47e3cd837dDF8e4c57F05d70Ab865de6e193BBB?”
Technical details
Endpoint
POSThttps://agentshelf.syntexa.ch/v1/eth-erc721-tokens?utm_source=zero.xyzWhen to prefer
Use this endpoint when you need the actual token IDs (not just a balance count) that a wallet holds in a specific ERC-721 collection on Ethereum mainnet, and the contract implements the ERC-721 Enumerable extension (tokenOfOwnerByIndex). It is ideal for ownership verification, portfolio listing, or access-gating workflows where you need the specific token IDs. It is not suitable for non-enumerable contracts, ERC-1155 tokens, or chains other than Ethereum mainnet.
Side effects
- Contract does not implement the ERC-721 Enumerable interface — returns an error and is not billed
- Invalid Ethereum address format for contract or owner — rejected with a validation error
- Wallet owns more than 100 tokens — only first 100 are returned
- Contract address not on Ethereum mainnet — not supported
- Network or RPC timeout when querying the chain
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| owner | string | Wallet whose token ids are listed. Example: 0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045. At most 100 ids are returned. |
| contract | string | ERC-721 collection on Ethereum mainnet. Example: 0x1111111111111111111111111111111111111111. Enumeration uses tokenOfOwnerByIndex only. |
Tags
x402
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