ERC-20
/ee-ar-see TWEN-tee/ · noun · Development · Origin: 2015
Definitions
The dominant token standard on Ethereum, defining a common interface (transfer, approve, balanceOf, etc.) that allows any compliant token to be traded, stored, and composed with other contracts interoperably. Its simplicity drove the 2017 ICO boom but also enabled countless scam tokens, since anyone can deploy an ERC-20 in minutes.
In plain English: A set of rules that tokens on Ethereum must follow so they all work the same way. It's why you can use any Ethereum wallet to hold thousands of different tokens.
Example: The project launched their governance token as an ERC-20, which meant it was instantly compatible with every DEX and wallet in the Ethereum ecosystem.
Origin Story
The 9-function interface that standardized crypto tokens
Fabian Vogelsteller and Vitalik Buterin proposed **ERC-20** (Ethereum Request for Comments #20) in November 2015. Before this standard, every token on Ethereum had its own unique interface, making wallets and exchanges implement custom code for each token.
ERC-20 defined just nine functions and two events: `totalSupply`, `balanceOf`, `transfer`, `approve`, `transferFrom`, and a few others. This minimal interface was enough for any wallet or exchange to support any compliant token without custom integration.
The standard enabled the 2017 ICO boom -- anyone could create a token in minutes. Thousands of tokens launched, from legitimate projects to outright scams. ERC-20's simplicity was both its genius and its curse: it standardized value transfer but couldn't prevent fraud.
Coined by: Fabian Vogelsteller, Vitalik Buterin
Context: Ethereum GitHub, November 2015
Fun fact: The '20' in ERC-20 is simply the GitHub issue number where it was proposed. ERC-721 (NFTs) is issue #721. There's no significance to the numbers -- they're just sequential GitHub issue IDs.