Generate a diceware passphrase
Memorable, high-entropy passphrases — random common words joined by a separator. Configure word count, separator, and optional number/symbol. Runs locally.
How diceware works
Pick N random words from a wordlist of W. Each word contributes log2(W) bits of entropy — 5 common words gets you ~50 bits.
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Choose words
4 minimum for casual, 7+ for high-security.
Inputs are treated as UTF-8 throughout the pipeline and validated client-side as you type — nothing dispatches until the value is well-formed.
countinpututf-8client-sidevalidatedn · text5 · set5 words
loaded · parsedclient-side - 02
Pick separator
Space, dash, underscore, dot.
Each toggle re-computes through a memoised hook, so flipping options never resets your input and the UI stays snappy on large inputs.
sepoptionslivememoisedtogglessep · memoised- · liveword-word
options set · memoisedlive - 03
Add number/symbol
Boosts entropy and satisfies password policies.
Randomness — where used — comes from
crypto.getRandomValues, neverMath.random. Heavy work sits inuseMemo.mixcomputeinstantlocaldeterministic+ · instantnum sym · computed…42!
computed · instantinstant - 04
Generate & store
Save in your password manager.
Copy writes through
navigator.clipboardand downloads use aBlob— zero network traffic. Same input plus same options always yield the same bytes.savecopydownloadzero-networkreproducibleok · copiedready · copiedCopied
shipped · ready to shipsuccess
Pro tips for everyday utilities
Reach for crypto.getRandomValues
Cryptographically random for IDs, tokens, salts. Math.random is for animation and games, not security.
Mock data with seeds
Faker-style libraries can be seeded so tests are reproducible. Embed the seed in the fixture file.
Reference cards beat memory
Cheatsheets for Vim, Git, Docker, Linux signals are faster than man pages when you’re mid-flow.
Browser APIs vary
Touch events, gamepads, and clipboard differ across vendors. Feature-detect before use.
Persist in the right place
localStorage for user preferences, sessionStorage for transient state, IndexedDB for structured data.
When to use a passphrase
Master password, vault, recovery.
Manager master
High-entropy and memorable, not pasted from a doc. Random values come from crypto.getRandomValues — cryptographically secure for tokens, salts, and session IDs. Math.random is deterministic enough for animations but predictable enough to be a security bug.
CSPRNG-backedDisk encryption
FileVault / LUKS / BitLocker pass-phrases. Pair with hashids, ULID, or UUID v7 when you need both random and sortable — useful for primary keys, public-facing IDs, and event log ordering without a sequence column.
reproducibleBackup recovery
Long, easy-to-type secrets for cold storage. Output is deterministic given the same seed, so fixtures and tests stay reproducible across CI runs and contributor machines. Embed the seed in the fixture file for full replay.
snappySSH keys
Wrap a private key with a memorable phrase. Heavy work runs through useMemo so the UI stays snappy on large inputs. Same input + same options yields identical bytes — the kind of stability snapshot tests rely on.
feature-detectedWallet seeds
Adds entropy to crypto seed backups. Storage tools persist to the right backend: localStorage for user preferences, sessionStorage for transient state, IndexedDB for structured data. Pick the right shelf and quota worries disappear.
deterministicTeam handoff
Easier to read aloud than a random string. Browser feature detection: clipboard, fullscreen, gamepad, and Web Bluetooth APIs gracefully fall back when unavailable. No surprise white screens on Safari or older Firefox.
production-readyFrequently asked questions
Something missing?
Tell us what you need. We ship the top requests every two weeks.