Overview
ERC-20 is the most widely recognized technical standard for creating fungible tokens on the Ethereum blockchain. Initially proposed in 2015 via Ethereum Improvement Proposal 20, it provides a universal framework that allows developers to issue digital assets that are interchangeable and uniform. Because every token unit is identical in value and function to any other unit of the same token, ERC-20 assets are ideal for representing currencies, loyalty points, or voting rights within decentralized ecosystems.
The standard was developed to address the lack of consistency among early Ethereum tokens, which often required custom code for every new integration. By establishing a common language, ERC-20 ensures that various tokens can be easily supported by wallets, exchanges, and smart contracts without the need for specialized programming for each individual asset. This uniformity has made it the foundational pillar for the majority of tokens currently circulating on the Ethereum network and its various compatible layer-two solutions.
Specification
The ERC-20 specification defines a specific set of functions and events that a smart contract must implement to be considered compliant. These functions include basic operations such as retrieving the total token supply, checking the balance of a specific address, and executing transfers between users. The standard also includes a mechanism for delegated transfers, where a token holder can approve a third party, such as a decentralized exchange, to spend a certain amount of tokens on their behalf.
In addition to the mandatory functions, the standard allows for optional metadata that improves user experience and readability. Developers typically include a token name, a ticker symbol, and the number of decimal places the token supports. These details allow external applications to display token information accurately to users. The specification relies on triggered events to notify the blockchain whenever tokens are moved or approvals are granted, ensuring that off-chain services can track token activity in real-time.