A random password or an easy-to-type passphrase. Made in your browser, never sent anywhere.
Everything happens on your device. The page uses your browser's cryptographic random number generator (crypto.getRandomValues) and sends nothing back to the server. Results are not stored; only your chosen options are remembered in this browser.
A password of 20 characters from all four groups gives about 125 bits of entropy, far beyond what anyone can guess. A passphrase of five random words from a 7,776-word list gives about 65 bits, which is plenty for most accounts and much easier to type on a phone or TV. Use six or more words for a password manager or disk encryption.
Each site should get its own password. A password manager remembers them for you; this page only makes them. Read how to share secrets safely if you need to send one to someone, or use a self-destructing note.