What is ERC-20?

The most common fungible-token standard on Ethereum and its compatible chains.

ERC-20 defines a minimal interface for fungible tokens: transfers, approvals and balances. Most tokens you see on Ethereum and its layer-2s use it.

It has known rough edges, notably that a transfer to a contract can succeed while the tokens are stuck. Later standards added hooks to prevent that.

Token standardTokens
A shared contract interface, such as ERC-20, so wallets and exchanges can support a token.
Token approvalSecurity
Permission you grant a contract to move a token of yours, sometimes without a limit.
Gas feeOn-chain
The fee paid to have a transaction included in a block; priced by network demand.

See it on a coin page