ERC-721
The Ethereum token standard for non-fungible tokens (NFTs). Unlike ERC-20 tokens where each unit is identical, each ERC-721 token has a unique identifier making it one-of-a-kind. The standard defines functions for transferring, approving, and querying ownership of individual tokens, enabling digital art, collectibles, and unique digital assets.
“Every Bored Ape Yacht Club NFT is an ERC-721 token with a unique token ID. Even though they're part of the same collection, each is a distinct on-chain asset with its own ownership record.”
NFT (Non-Fungible Token)
A unique digital token on a blockchain that represents ownership of a specific item — such as art, music, collectibles, virtual real estate, or in-game items. Unlike fungible tokens like BTC or USDC where each unit is identical, each NFT has a unique identifier making it one-of-a-kind. NFTs typically follow the ERC-721 or ERC-1155 token standard and store metadata pointing to the associated content.
Token Standard
A set of rules defined in a smart contract interface that tokens must implement to be compatible with the broader ecosystem of wallets, exchanges, and dApps on a blockchain. Standards ensure interoperability — any application built to support a standard automatically works with all tokens following it. Major Ethereum standards include ERC-20 (fungible), ERC-721 (NFT), and ERC-1155 (multi-token).
ERC-1155
A multi-token standard on Ethereum that can represent both fungible and non-fungible tokens within a single smart contract. ERC-1155 is more gas-efficient than deploying separate ERC-20 and ERC-721 contracts, and supports batch transfers, making it popular for gaming assets and collections with varying rarity levels.
Smart Contract
Self-executing programs stored on a blockchain that automatically enforce the terms of an agreement when predetermined conditions are met. Smart contracts enable trustless transactions without intermediaries because the code, once deployed, executes exactly as written and cannot be altered (unless specifically designed to be upgradeable). They form the foundation of DeFi, NFTs, DAOs, and virtually all dApps.