What are those 12 or 24 words your wallet wants you to write down?
When you set up a crypto wallet (Ledger, Trezor, MetaMask, Phantom, Exodus), the device shows you a list of words: 12 or 24 ordinary English words like "abandon ability acid...". That's your recovery phrase: the only way back to your coins if the wallet dies, you lose the phone, or forget the PIN.
Under the hood that's the BIP39 standard. Since 2013, every serious crypto wallet stores access this way. Words always come from a fixed list of 2,048 English words, and one of them is a checksum (a built-in correctness check). That's why you can't just make up a phrase off the top of your head, it has to *"add up"* mathematically.
This tool does two things: generate a fresh phrase (for a new wallet, for testing, for learning), or validate a phrase you already have written down (does it actually work?). Everything runs in your browser, no word ever leaves your device. You can even turn off Wi-Fi after the page loads and the tool keeps working.
How to use it
- "Generate" mode: pick 12 or 24 words and click Generate. The randomness comes from your browser's cryptographic generator (the same one banks use). Every click = a new, unique phrase.
- "Validate" mode: paste your words (separated by spaces or newlines, case doesn't matter). The tool tells you immediately whether the phrase is valid and exactly which word is wrong if there's a typo somewhere.
- If the phrase is meant for a real wallet, generate on an offline computer, ideally from a Tails USB or a freshly wiped device. Write it down on paper (not on your phone, not in a file, not in email). Stash it in a safe or a bank deposit box.
- For learning or for a test wallet (e.g. dev networks like Sepolia, or mainnet with a tiny test amount) feel free to use what you generate here, as long as you don't load it with real money.
- Never type your real recovery phrase into random websites, *"support"* chats, or emails. No honest support team ever asks for your phrase, not from a wallet vendor, not from an exchange.
When this is useful
Seven typical situations where this tool saves your skin:
- Verifying a phrase your relative wrote down. Your dad bought a Ledger, scribbled 24 words on a card with shaky handwriting. Before panicking, paste it here and check whether every word is on the list and whether the phrase as a whole *"adds up"*. You'll catch "witnesses" instead of "witness", the kind of typo that quietly costs people millions.
- Generating a fresh seed for a new cold wallet. Bought a Ledger second-hand? Never use the phrase that came with the device (it might have been recorded by the seller). Generate a new one here, write it on paper, restore it onto the device. Real security starts with your own randomness.
- Learning how wallets work under the hood. Taking a Solidity course, building a Web3 side project, studying crypto for a class. Generate a test phrase, paste it into MetaMask, watch what addresses come out of it. No panic about losing real money.
- Testing a dev wallet. Building a Web3 app and you need seeds for automated tests. Generate as many as you want, no rate limits, nothing sent to any server.
- Making a backup of your backup. Your phrase is engraved on a steel plate, but you can't quite tell if the last word is "zone" or "zoo". Paste what you have, try the candidates, the tool tells you which one is mathematically valid. (Heads up: this trick reveals the phrase, so do it only offline.)
- **Confirming your *"second seed"* is actually different**. You migrated to a new Ledger Stax and you're worried the new phrase might accidentally be the same as the old one. Paste both back-to-back, compare them by eye.
- Team training / company onboarding. You work at a crypto company and need to show new hires what a recovery phrase looks like, why it never goes into cloud storage, why a typo means losing the coins. A live tool beats 200 slides.