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History for this tool
The most recent data you entered in this tool, stored only in this browser.
Save what you type here, in this browser? Your work would go into this browser's local storage, so a refresh or a trip to another tool does not wipe it. You also get a short list of previous entries under the form, each one restorable with a click. Nothing is ever uploaded, and there is no account.
Being straight about the trade-off: anything kept there can be read by anyone who can use this browser profile, and by any script that later runs on this site. A tool page can hold a private key, a password or a signed token. Saving is convenient; it is not private.
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Your inputs and history are stored locally.
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About this tool
Generate a BIP-39 mnemonic phrase from a chosen word count and derive the seed from it, which is how a cryptocurrency wallet backs up a key as words. It also checks a phrase you were given for a valid checksum.Questions
- Is it safe to generate a wallet seed in a browser?
- The entropy comes from crypto.getRandomValues, so the randomness is real. The risk is the page and the machine, not the maths. For anything holding real value, generate offline on a machine you control.
- Why does it reject my phrase?
- The last word carries a checksum. If one word was mistyped the checksum fails and the phrase is rejected, which is the feature working as intended.