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Decoding the Mysteries of xPub, yPub, zPub, and UTXO: A Beginner's Guide

xPub, yPub, zPub, and UTXO


Navigating the world of cryptocurrencies can be a daunting task, especially when you encounter terms like xPub, yPub, zPub, and UTXO. These terms are crucial for understanding how Bitcoin wallets function, particularly in terms of security and transaction efficiency. This article aims to demystify these terms and provide a comprehensive understanding of their roles in the Bitcoin ecosystem.

What Are xPub, yPub, and zPub?

Extended Public Keys, commonly known as xPub, yPub, and zPub, are identifiers for different types of Bitcoin addresses. These keys are part of Hierarchical Deterministic Wallets (HD Wallets), which automatically generate a structure of child private and public keys from a single master seed.

  • xPub: This is the oldest format and is used for generating legacy addresses that start with the number "1".

  • yPub: Introduced after the adoption of SegWit, yPub keys generate addresses that start with the number "3" and are backward-compatible.

  • zPub: The newest format, zPub keys generate native SegWit addresses that start with "bc1".

Each of these keys can only generate one type of address: legacy, SegWit, or native SegWit. The type of address they can generate is determined by the first four characters in the extended public key.

Understanding UTXO

UTXO stands for Unspent Transaction Output. In simple terms, UTXO represents the unspent funds in your wallet and is crucial for executing transactions. When you make a transaction, the UTXO is used as the input, and new UTXO is generated as the output.

Why Are These Keys Important?

  1. Security: These keys allow you to have a read-only view of your wallet's transactions and balances without exposing your private keys. This is particularly useful for monitoring your wallet without risking your funds.

  2. Efficiency: Different types of keys are optimized for transaction speed and cost. For example, native SegWit addresses generated by zPub keys offer the smallest transaction fees but are not backward-compatible.

  3. Flexibility: Even if your wallet provider only gives you an xPub key, it can be converted into yPub or zPub formats using specific tools and libraries, allowing you to choose the type of addresses you want to generate.

How to Find and Use These Keys

If your wallet provider only offers an xPub key, don't worry. There are tools and libraries available that can convert your xPub key into yPub or zPub formats. Once converted, you can use these keys to generate new addresses or monitor existing ones.


Understanding xPub, yPub, zPub, and UTXO is crucial for anyone involved in the Bitcoin ecosystem. These keys and identifiers not only enhance the security of your transactions but also offer flexibility and efficiency in managing your funds.

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