Interactive demo · try it yourself
Watch a seed get born
You've read that your seed words are your key. This page shows you how — a real seed phrase built in front of you, one step at a time, from pure randomness to 12 words to a Bitcoin address.
The seed below is randomly generated in your browser and thrown away the moment you leave. Never type your own seed words into any website — including this one. Notice there's no input box here: that's on purpose. A guide that asks for your seed is a guide trying to rob you.
Ready? We'll flip 128 digital coins and turn them into a seed phrase.
Runs entirely in your browser · nothing is sent, saved, or logged.
A seed phrase isn't assigned by a company — it's just an enormous random number, rewritten as words so
a human can copy it. The same words rebuild the same wallet, on any brand of device.
That's why the words are the backup, and why guarding them is the whole game.
One qualification, because it is the half people are surprised by later: that holds for the words
alone. Add a passphrase — the optional extra secret a later lesson covers — and the same words plus a different
passphrase rebuild a different wallet, with no error and nothing to tell you which one you are in. The words
are the backup; if you ever add a passphrase, it is part of the backup too.
← Back to how it all works See the checksum catch a typo → How to back yours up →
✓ Last verified: July 31, 2026