Ian Coleman BIP39 tool for offline seed checks

Swiss angle

The BIP39 tool is a global project by one developer, Ian Coleman, with no Swiss base. The repository on GitHub, read on 4 October 2026, says the tool is released under the MIT licence. It is a single web page that runs in your browser; it holds no coins and has no customers, so it is not a financial service.

No fetched page names a Swiss price or office. The tool works on the BIP39 standard, which every modern wallet uses the same way in every country. The chapter on wallets and staying secure explains what a seed phrase is and why it is the wallet.

The tool has not changed in a while. The latest release on GitHub, version 0.5.6, was published on 1 August 2023, and the repository shows its last push on 28 April 2024.

Who it is for

People who need to check what a seed phrase derives, on a computer that is not online. The tool page shows the keys and addresses for a given phrase, which helps when you want to confirm that a backup matches the receive addresses your wallet showed you.

People recovering coins from an old wallet. If you know your words but not the derivation path the old app used, the tool page has tabs for the BIP32, BIP44, BIP49, BIP84 and BIP141 paths, so you can try each until the addresses match. The wallet recovery guide explains why the same 24 words can lead to different addresses.

Learners who want to see BIP39 at work with a throwaway phrase. Generate a new random phrase on the page, never a real one, and watch how the words become a root key and then addresses.

Who it is not for

Anyone about to type a real seed phrase into the online page. btc2h's rule: never enter a phrase that holds funds into iancoleman.io in a connected browser. Download the file, move it to a computer that is offline, and open it there. The tool page describes that route under Offline Usage: save the page as a file, or download the file from the latest GitHub release, then open it in a browser on any offline computer. The README names the file to download as bip39-standalone.html.

Anyone who has been asked for their words. The tool page warns that if you share the information it generates with anyone, they can steal your assets, and that anyone asking for your secret recovery phrase or BIP32 root key is a scammer. It also says not to copy and paste its output or send it to anyone offering help on Twitter, Discord, Telegram, Etherscan or Line.

People who want a wallet. The tool shows keys; it does not track a balance or send coins. To use your phrase day to day, restore it into a BIP39-compatible wallet; the wallet recovery guide explains that any such device derives the same addresses from the same words.