what is public key / xpub?

a key that lets a wallet see an account's addresses and balances, but not spend.

an xpub (extended public key) can't spend on its own, but it reveals every balance and the transaction history of the account, and together with any one leaked private key from that account it can expose them all. treat it as private: share it only with software you use for watch-only or multisig.

related words

private key the secret that authorises coins to move from an address.
wallet software or a device that holds (or can recreate) your keys, shows balances and signs transactions.
custodial a setup where a company, usually an exchange, holds the keys and you hold an account.

part of the topic self-custody: free articles, more words and the guide.

checked 2026-10-20. education, not advice. found a mistake? see corrections.