YSeed
BIP39 English / browser-only / no server custody

Free BIP39 seed phrase generator

A calm, trust-first utility for generating BIP39 phrases locally with Web Crypto. No account, no phrase API, no server custody.

Trust contractGenerate, verify, write down, wipe. Nothing leaves this device.
Runtime
Static app
Phrase state
JS memory
Saved data
Theme only
No accountsNo phrase APINo phrase storageOffline-ready

Generation chamber

Create the phrase locally.

Web CryptoMemory only
Ready for a private screen.Generate after you close screen sharing and cloud notes.

Clipboard can sync across devices. Copy only for tests or offline use.

24 words

256 bits of entropy plus 8 checksum bits.

Entropy256 bits
Checksum8 bits
WordlistEnglish 2048

Safety controls

Default-deny by design.

locked
  1. 01Private screen
  2. 02Generate offline
  3. 03Write on paper
  4. 04Wipe screen

Live privacy receipt

What the page is allowed to know.

no telemetry
Random sourceChecking Web Crypto
Connectionlocal first
Requests after load0 captured
Phrase storageMemory only
01

No seed phrase backend.

YSeed is a static client-side tool. V1 has no account system, database, wallet lookup, or endpoint that receives a phrase.

  • Generation happens in the browser.
  • Validation checks words and checksum locally.
  • No address lookup or wallet balance check.
02

No persistence.

Generated seed phrases are not written to localStorage, sessionStorage, cookies, or the URL. Only the visual theme preference is saved.

03

Offline ceremony.

Load once, disconnect, generate, write down, validate if needed, then wipe the screen. Treat clipboard as unsafe unless you are testing.

BIP39 Validator

Check word count, English wordlist membership, and checksum. For the dedicated workflow, open the BIP39 validator or follow the offline verification guide. Do not paste a real wallet recovery phrase into any live website.

Paste or type a phrase to inspect it.

Use demo or test phrases only in the live website. Real wallet recovery phrases belong offline.

No server checksNo address lookup

What is YSeed?

YSeed is a free, client-side BIP39 seed phrase generator for education, test wallets, and offline generation workflows. It creates phrases entirely in your browser using the Web Crypto API.

The trust-first rule is simple: the app should help you generate and understand a phrase without becoming a new place where that phrase can leak.

How YSeed generates BIP39 phrases

  1. Select 12, 15, 18, 21, or 24 words.
  2. Generate entropy locally with crypto.getRandomValues().
  3. Add BIP39 checksum bits and map 11-bit chunks to the English wordlist.
  4. Write the phrase offline and wipe it from the interface.

Learn the trust-first workflow

Use the generator, then read the safety model behind it. YSeed is intentionally narrower than a wallet recovery suite.

BIP39 generatorBIP39 wordlistSecurity modelLearning hubGeneration methodologyOffline ceremonyOnline generator safetyBalance-check scam warningVerify a phrase offlineCompare BIP39 tool typesBIP39 checksum12 vs 24 wordsAbout YSeed

BIP39 English wordlist

Search the same 2048-word list used by the generator and validator, or open the complete numbered BIP39 wordlist.

Showing words