ERC Standards, Explained
ERC stands for Ethereum Request for Comment. It's basically a rulebook that developers agree to follow, so different tokens and apps can work together properly.
Think of it like a universal plug shape. If everyone builds to the same standard, anything can connect to anything else, wallets, exchanges, marketplaces, without each one needing custom code just to talk to a new token.
Below are the standards that actually matter for understanding what's happening on Ethereum today.
ERC-20 — Fungible Tokens
ERC-20 is the most common standard on Ethereum, and it's what most people mean when they say "token." Fungible just means each unit is identical and interchangeable, the same way one dollar bill is worth exactly the same as any other dollar bill.
USDC, most DeFi tokens, and most tokens traded on exchanges follow the ERC-20 standard. If a wallet or exchange supports ERC-20, it can support virtually any token built to that same standard, without needing custom code for each one.
ERC-721 — Non-Fungible Tokens (NFTs)
ERC-721 is the standard used for unique, one-of-a-kind digital assets. Unlike ERC-20 tokens, no two ERC-721 tokens are identical. Each one has its own ID and its own record of ownership.
This standard is what powers NFTs, digital art, collectibles, event tickets, and increasingly, tokenized real-world items like a deed or a certificate of ownership. One ERC-721 token cannot be swapped for another the way currency can, since each one represents something distinct.
ERC-1155 — Multi-Token Standard
ERC-1155 is a hybrid standard that can represent both fungible and non-fungible items within a single contract. Instead of needing separate contracts for currencies and unique items, one ERC-1155 contract can handle both at once.
This standard shows up most often in gaming and digital collectibles. A game could use ERC-1155 to manage a stack of 500 identical swords alongside a single, one-of-a-kind legendary sword, all within the same efficient system.
ERC-4626 — Tokenized Vaults
ERC-4626 is a newer standard built specifically for yield-generating vaults, the kind of contracts used in DeFi lending, staking pools, and other places where people deposit assets to earn a return over time.
Before this standard existed, every vault worked a little differently, making it harder for apps to safely plug into different vaults without custom integration work. ERC-4626 gives vaults a consistent, predictable structure, so wallets and other apps can interact with them more safely and easily.
ERC-8004 — Agent Identity
ERC-8004 is a brand-new standard built for a very different kind of user: AI agents. As autonomous AI systems increasingly interact with Ethereum, buying data, paying for services, completing tasks, they need a way to prove who they are and build a trustworthy track record, just like a person or a company would.
ERC-8004 gives AI agents an on-chain identity, verification, and reputation system. It's still early, but it's part of a larger shift we cover in our AI Agents section, where software itself is becoming a real participant in Ethereum's economy, not just a tool humans use to access it.
A quick note on safety: following one of these standards only defines how a token technically works, not whether the people behind it are trustworthy. A scam token can be perfectly valid ERC-20 code and still be worthless or fraudulent.
Standards tell you the shape of the thing. They don't tell you if it's safe. Always research a project independently before interacting with any token, no matter which standard it follows.