ERC-721 NFT Standard

ERC-721 is a standard for representing the ownership of different unique tokens, also known as “non-fungible tokens”. Tokens made to the ERC-721 standard are indivisible, distinguishable, and can represent a collection of assets. An ERC-721 token can also have different value than another token from the same smart contract.

Blockchain Ethereum
Type Non-fungible
Popular token Skullpunks-Og
Required Functions name, symbol, totalSupply, balanceOf, ownerOf, approve, takeOwnership, transfer, tokenOfOwnerByIndex, tokenMetadata
Released 2018
Use cases Collectables, Crypto games, Ownership
Explore ERC-721 APIs

Build with ERC-721 tokens on CryptoAPIs

Now that you know what ERC-721 is, integrate it: read ERC-721 token transfers, balances, and contract metadata across supported chains through one REST API.

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ERC-20
ERC-721
TRC-20
TRC-721
BEP-20

Work with ERC-721 tokens via the CryptoAPIs API

Read ERC-721 token transfers, balances, and metadata across the chains CryptoAPIs supports — through one unified REST API, with no node to run.

Token transfers

List full ERC-721 token transfer history for any token contract or address, with pagination and real-time updates.

Token balances

Read current ERC-721 token holdings for any address in a single call.

Contract metadata

Get token contract details — symbol, name, decimals, and total supply — for any supported token.

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The standard of unique tokens

ERC-721 tokens are mostly used for collectables and as a way to tokenize unique items and assets in digital games. The standard provides basic functionality to transfer and track the ownership of NFTs.

Frequently Asked Questions

Which blockchain does ERC-721 run on?

ERC-721 settles on Ethereum. Because every token is distinct, transfers are tracked per token id rather than by amount, and a wallet's holding is a list of ids rather than a single number.

What kind of token standard is ERC-721?

It is a non-fungible interface — each token has its own id and owner.

Can I test ERC-721 without spending real funds?

Yes — the same endpoints serve Ethereum's Sepolia testnet, so you can build and verify an integration end to end before you touch mainnet.

How do I read ERC-721 balances and transfers?

Use Address Latest for current state and recent activity — it needs no setup and answers for roughly the last 14 days. For a full history, Address History requires the address to be synced first, which then bills per address per day for as long as it stays synced.

What does reading ERC-721 data cost?

It depends on the endpoint family rather than on ERC-721 itself: single-record calls are charged per request, while list endpoints are charged per page returned, and a synced address adds a daily monitoring charge. The pricing calculator has the current per-chain figures.