Ethereum's token standards are undergoing a major upgrade. Starting with ERC-20 in 2015 for fungible tokens and ERC-721 in 2018 for non-fungible tokens (NFTs), the latest ERC-6551 standard transforms NFTs into self-contained wallets that can own other assets.
How ERC-20 and ERC-721 Shaped the Ecosystem
ERC-20 set clear rules for issuing and transferring fungible tokens. Today, major assets like Chainlink, Uniswap, and USDC all run on this standard, making them instantly compatible with wallets, exchanges, and DeFi protocols. ERC-721, launched in 2018, pioneered the NFT era by creating a standard for unique digital items. Iconic collections such as CryptoPunks and Bored Ape Yacht Club owe their existence to ERC-721, which stores distinct metadata per token.
ERC-6551: The Token Bound Account Revolution
The newest addition, ERC-6551, introduces what developers call "Token Bound Accounts". Each NFT becomes an independent Ethereum wallet address, capable of holding ERC-20 tokens, other NFTs, or any on-chain asset. This opens possibilities like a gaming character carrying its inventory directly on-chain, or a digital identity NFT storing verifiable credentials.
While still early-stage, ERC-6551's potential stretches across gaming, DeFi, and digital identity. The standard essentially gives NFTs agency beyond collectibility.
Where Each Standard Excels
ERC-20 remains the backbone of DeFi, powering stablecoins and governance tokens. ERC-721 dominates NFT marketplaces, while ERC-1155 and ERC-6551 gain traction in gaming for managing multiple asset types. Together, these standards ensure interoperability and security across Ethereum's diverse applications, providing a shared technical language that empowers developers.