BIP39 Builder

A web tool for building custom BIP39 mnemonics.

This tool allows you to generate and customize BIP39 mnemonic seed phrases used for creating and/or recovering a Groestlcoin deterministic wallet.

• Choose between 24, 21, 18, 15, and 12 words
• Generate a complete random phrase at any time
• The button will use the browser's random number generator
• The text input will use the SHA-256 hash of whatever you type in (should be something random, or very long)
• Drop down interface for selecting and searching for individual words
• The list of valid last words will dynamically update as word selections are made
• Once all words are selected, a summary is shown which helps visualize the mapping between the data and words. The seed is also shown with an optional passphrase input, which can then be used with BIP32 for generating a deterministic wallet.

This application is MIT licensed. There is no warranty and no party shall be made liable to you for damages. If you lose coins due to this app, no compensation will be given. Use this app solely at your own risk.

Note: Choosing your own mnemonic is less secure than using a randomly generated one. There is a greater chance an attacker can guess your phrase if it is not random. On the flip side, there is also a greater chance of remembering a custom phrase in case you lose your backups by accident. Overall, random is still better, but if you're willing to accept the tradeoffs, a custom mnemonic can be useful. It is another tool to have in the wide spectrum of security systems.

Source code: