What is xpub?

An xpub, short for extended public key, is a single key from which every receiving address of a Bitcoin account can be derived. A Bitcoin wallet rotates addresses, handing out a fresh one for each deposit, and the xpub is what lets a watcher generate the whole sequence without holding any private key. It is the reason a watch-only wallet can show your full balance across dozens of addresses from one string.

It is powerful precisely because it is a privacy trade. Anyone holding your xpub can see every address the account has used and every address it will use in future, and can therefore follow your entire history and all future activity of that account. It cannot spend a satoshi, but it removes the privacy that address rotation exists to provide. Sharing an xpub with a service is a decision to trust that service with the full picture of one account, forever.

Hardware wallets such as Ledger and Trezor expose the xpub of each account in their companion apps, and many portfolio trackers accept it as a shortcut. The alternative is to paste the individual receiving addresses you actually use, which reveals only those addresses and nothing about future ones. It is more work for a busy wallet and more private for every wallet.

TrueHold reads addresses, not xpubs. Paste the Bitcoin addresses that hold your coins and they are totalled together; the extended key stays in the wallet. It is more typing for a wallet with a long history, and it means no service ever holds the key that maps your whole future, which is the point of address rotation in the first place. The hardware wallet coverage pages explain the workflow for Ledger and Trezor, and the xpub explainer in the blog goes into the derivation in more depth.