EOA

EOA, in blockchain terminology, stands for Externally Owned Account. In Ethereum and similar networks, an EOA is an account controlled by a private key rather than by code. An EOA is typically used by individuals and wallets to hold and transfer funds. Each EOA has an address, usually a 20-byte hexadecimal string (0x…) derived from the account's public key. The public key itself is revealed when the account signs a transaction.

An EOA can send transactions to transfer Ether, interact with smart contracts, or approve token transfers. Transactions from an EOA require gas and are authorized by the owner's private key through a cryptographic signature. Each transaction increments the account's nonce, helping preserve proper ordering and preventing replay. EOAs do not contain executable code; they have no state beyond balance and nonce. In contrast, contract accounts run code stored on-chain and can act autonomously when invoked by transactions.

EOAs interact with contract accounts by sending transactions that trigger code execution, and they pay gas fees in Ether. The security of an EOA rests on protecting the private key; loss or theft allows unauthorized access to funds. Common protection methods include hardware wallets, multi-signature schemes, and secure seed phrase backups. If a private key is compromised, the attacker can drain the account, since EOAs have full control over their funds.

In Ethereum, EOAs contrast with contract accounts and are the typical means by which users initiate on-chain activity. The term EOA is used mainly in this context; in other domains the acronym can have different meanings.