Password Generator

How this actually works, for the curious

• True randomness. Every character and every passphrase word comes from crypto.getRandomValues() — the Web Crypto API's cryptographically secure RNG, the same primitive browsers use to generate TLS keys. Not Math.random(), which is fast but was never designed to be unpredictable.
• No modulo bias. Mapping a random byte onto, say, a 70-character alphabet the naive way (byte % 70) makes some characters land slightly more often than others. This tool uses rejection sampling instead — discarding the handful of byte values that would introduce that skew — so every character in the pool is exactly equally likely.
• Guaranteed coverage, still random. Ask for lowercase + uppercase + numbers + symbols and the password is guaranteed to contain all four, without ever putting them in predictable positions: one character is drawn from each required set, the rest from the combined pool, and the whole thing is shuffled with a CSPRNG-driven Fisher–Yates shuffle.
• Passphrases use BIP-39. The word list is the same 2048-word list cryptocurrency hardware wallets use for seed phrases — curated to avoid similar-looking or similar-sounding words, and sized to exactly 2¹¹, so picking a word needs no rejection sampling at all: mask 11 random bits and you're done, with mathematically zero bias.
• Nothing leaves your device. This entire tool runs in your browser tab. No password, passphrase or setting is ever sent to a server, logged, or stored anywhere — not even locally. Close the tab and it's gone.

One honest caveat: the strength meter shows entropy — mathematical randomness — not a guarantee against every attack. Reusing a strong password across sites, or typing it into a phishing page, defeats all of this. Store what you generate here in a password manager, and turn on two-factor authentication wherever it's offered.