What is an extended public key (xpub)?

An extended public key, or xpub, lets an app derive every receiving address of a wallet without being able to spend. Anyone who has it can see all of the wallet’s addresses and their full history.

Also called xpub, zpub or master public key.

Why apps ask for it

Watch-only wallets, portfolio trackers, accounting tools and multisig coordinators use the xpub to follow every address of a wallet as it creates new ones.

The privacy cost

Whoever holds your xpub sees every past and future address, balance and payment of that wallet, which is far more than any single address gives away.

The quantum angle

An xpub also reveals the public key behind every address it derives, so a wallet that has shared it has no hidden keys left. With normal derivation, an xpub together with one leaked child private key reveals the parent key as well.

In Redacted

If you move coins for bunker mode from a wallet whose xpub you have shared, take the fresh address from a new seed. In bunker mode your Redacted account is 25 words of its own and never derived from a wallet key.

Bunker mode →

Related terms

Exposed public keyA public key is exposed once it appears on the chain, usually the first time its address signs a transaction. Until then most addresses show only a hash of the key, which gives a key-breaking attacker nothing to start from.Address reuseAddress reuse means receiving more than one payment to the same address. Every payment to it is then linked to all the others, and to everyone who sent them.Chain analysisChain analysis traces funds on public blockchains and groups addresses into likely owners, using the public record together with outside data such as exchange records, address labels and leaks.Viewing keyA viewing key lets someone see the history of a private account without being able to spend from it, for example to show an accountant or an auditor exactly what happened.

Sources: BIP 32, Hierarchical Deterministic Wallets

Updated October 12, 2026. All terms