An xPub key, or extended public key, is a master public key that derives every address in a Bitcoin-style wallet. Connecting an extended public key — instead of one of the wallet's individual addresses — lets CoinTracker track every transaction and balance linked to that wallet without exposing your private keys.
Why connect an extended public key instead of a single address
In Unspent Transaction Output (UTXO)-based systems like Bitcoin, when a transaction occurs, the entire balance is transferred and any unspent amount is moved to a new, unused address.
For example:
- Carol has 10 BTC in Wallet A.
- She sends 7 BTC to Wallet B.
- The remaining 3 BTC are moved to a new Wallet C.
Wallet C is still part of Carol's wallet, but it has a different address than Wallet A. Connecting Carol's extended public key — rather than the Wallet A address by itself — lets CoinTracker track Wallet C and its 3 bitcoin balance automatically.
If you only connect one of those addresses to CoinTracker, three things can happen:
- Some sends and receives don't appear in your transaction history.
- A linked trade or swap looks broken because the matching transaction isn't visible.
- Your balance in CoinTracker doesn't match what your wallet shows.
If you're already seeing missing or unlinked BTC transactions on a connected wallet, check out the BTC transaction troubleshooting article to walk through what to check.
Types of extended public keys
The evolution of Bitcoin standards has created several types of extended public keys:
- xPub: Generates addresses prefixed with 1.
- yPub: Generates addresses prefixed with 3 (SegWit).
- zPub: Generates Bech32 addresses prefixed with bc1 (SegWit).
These variations offer better security and efficiency for managing transactions. Some wallets generate more than one extended public key — for example, one xPub for legacy addresses and one zPub for Bech32 addresses on the same wallet. Connect every key the wallet exposes so all addresses are covered.
Understand xPub key’s limits
Extended public keys are read-only. They let CoinTracker view every address, transaction, and balance linked to your wallet, but they can't initiate transactions or expose your private keys.
xPub keys don't apply to all blockchains. For example, Cardano uses an extended UTXO model with a stake key system instead of the xPub framework. Other blockchains use different address models that don't have an xPub equivalent.
If you run into any issues, please don't hesitate to reach out to our support team for help.