EIP-20 introduced the ERC-20 token standard. Proposed by Fabian Vogelsteller and Vitalik Buterin in 2015, EIP-20 defined a common interface for fungible tokens implemented through Ethereum smart contracts.
The standard specifies familiar operations such as transferring tokens, checking balances, approving a spender, and querying an allowance. It also defines Transfer and Approval events, which let wallets, exchanges, explorers, and other applications monitor token activity in a consistent way.
Its importance is interoperability. Before a widely adopted interface existed, each token contract could expose different functions, making wallets and applications harder to build. ERC-20 gave developers a shared convention, allowing many unrelated tokens to work with the same surrounding infrastructure. The standard was created on 19 November 2015.
A frequent mistake is choosing EIP-721 or EIP-1155. EIP-721 is associated with non-fungible tokens, while EIP-1155 supports a multi-token contract standard. EIP-1559 instead changed Ethereum’s transaction-fee mechanism; it did not define a token interface. “ERC-20” is the familiar name for the standard, while “EIP-20” identifies the proposal that specifies it.