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UUID + ULID generator.

Generate UUID v4, v7, and ULID identifiers in bulk. Includes a v7 / ULID timestamp decoder.

Type
Count
Format
0 generated
Hit Generate to see your IDs here.
Decode a v7 or ULID timestamp
UUID v7 and ULID embed a millisecond timestamp in their first bits — paste one above to read it.

What's the difference?

UUID v4 is 122 random bits. Great for security tokens; terrible for database primary keys (random insert order destroys B-tree locality).

UUID v7 packs a millisecond Unix timestamp into the high 48 bits, then random for the rest. Sortable by creation time, still globally unique, drop-in replacement for v4 in most APIs. RFC 9562 made it standard.

ULID is the same idea (timestamp + random) in Crockford base32 — shorter (26 chars vs 36), case-insensitive, URL-safe without encoding. Predates v7.

How it works

Pure browser, no server. v4 uses crypto.randomUUID() native. v7 packs Date.now() into the high 48 bits, sets the version + variant bits, and fills the rest with crypto.getRandomValues. ULID uses Crockford's base32 alphabet (no I, L, O, U) so handwritten IDs don't have ambiguous characters.

The decoder above extracts the timestamp from a v7 UUID (first 12 hex chars) or a ULID (first 10 base32 chars).

Planned

v0.1 · 2026