Roadmap › Blockchain & Web3 Fundamentals › Module: Ethereum in Depth
Lessons in this course (15)
7. Token standards: ERC-20, ERC-721, ERC-1155
Intermediate★ Must knowLesson 7 of 15
| Standard | Type | Key functions | Examples |
|---|---|---|---|
| ERC-20 | Fungible tokens (each unit identical) | totalSupply, balanceOf, transfer, approve, allowance, transferFrom; events Transfer, Approval | USDC, USDT, DAI, LINK, UNI |
| ERC-721 | Non-fungible tokens (unique IDs) | ownerOf, safeTransferFrom, approve, setApprovalForAll, tokenURI (metadata) | NFT art, tickets, domain names (ENS) |
| ERC-1155 | Multi-token (fungible + non-fungible in one contract) | balanceOf(account, id), safeBatchTransferFrom | Game items |
| ERC-4626 | Tokenised vaults | deposit, withdraw, convertToShares | Yield vaults |
| ERC-2612 | permit (gasless approvals via signatures) | permit | Many ERC-20s |
| ERC-4337 | Account abstraction (smart accounts) | UserOperations, bundlers, paymasters | Smart wallets |
Approve + transferFrom pattern: a user approves a DEX contract to spend N tokens, then the DEX pulls them. Unlimited approvals are a common risk — wallets that approved malicious contracts can be drained.
Stablecoins: tokens pegged to fiat (USDC, USDT — backed by reserves; DAI — crypto-collateralised).