UUID / ULID / NanoID GeneratorGenerate UUID v4, UUID v7, ULID, and NanoID values instantly, right in your browser.

UUID v4 is 122 bits of pure randomness in the familiar 36-character format, but its random order makes for poor database index locality. UUID v7 keeps that same shape while leading with a millisecond timestamp, so IDs sort roughly by creation time — handy for primary keys. ULID does the same time-first trick in a shorter, case-insensitive 26-character string. NanoID skips ordering altogether for a much smaller, fully customizable ID — you choose the length and character set.

Yes — every ID is generated with the browser's Web Crypto API (crypto.getRandomValues), the same source used for cryptographic keys, never Math.random(). UUID v4 and NanoID's default alphabet carry well over 100 bits of randomness. UUID v7 and ULID trade about 48 of those bits for a leading timestamp, so treat the timestamp-prefixed formats as sortable IDs rather than secrets.

Yes — switch to NanoID and this tool exposes a length slider (21 characters by default, matching the library) plus an editable alphabet field. Shrinking the length or narrowing the alphabet trades away collision resistance, so keep the length up if you cut the character set down.