Zpub (Extended Public Key)

A zpub is an extended public key whose SLIP-132 version prefix indicates native SegWit derivation under BIP 84, producing bech32 addresses that begin with bc1q. Like xpub and ypub it contains identical key material, a public key plus a 32-byte chain code; only the 4-byte prefix and the intended address type differ.

Why it matters

Native SegWit became the default address type for most wallets because it produces the smallest, cheapest transactions of the pre-Taproot formats, and the zpub prefix is how those wallets label their public key material. The label prevents a classic support nightmare: importing the same keys into software that derives the wrong address type shows an empty wallet, and users conclude their coins are gone when they are merely being looked for at the wrong addresses.

Like ypub, it is an industry convention layered on BIP 32 rather than part of bitcoin consensus, and output descriptors are gradually replacing the prefix system with explicit declarations.

How it works

BIP 84 wallets derive keys down the path beginning m/84', and the zpub serializes the account-level public key with version bytes that Base58-encode to the letters zpub. Converting between zpub and xpub is a matter of swapping those bytes, which many tools do when software insists on one form, and the private counterpart, a zprv, deserves the same protection as any extended private key.