UUID / ULID Generator
Generate cryptographically random UUID v4 identifiers or timestamp-sortable ULIDs, one at a time or up to 1000 in bulk, one per line. Copy or download the batch.
Bulk generation
UUID v4 is 122 bits of pure randomness in the familiar
8-4-4-4-12 hex format. Collisions are practically impossible and the value reveals nothing. Downside: random values scatter across a database index, which hurts insert locality on big tables.
ULID packs a 48-bit millisecond timestamp followed by 80 random bits into 26 Crockford Base32 characters. IDs created later sort later, both lexicographically and in binary. Prefer ULID when IDs double as a creation-ordered sort key: event logs, message queues, or B-tree primary keys where insert locality matters. Prefer UUID v4 when leaking creation time is unacceptable or when an ecosystem expects the standard UUID format.
Randomness: everything here uses
crypto.getRandomValues(), the browser's cryptographically secure generator, never Math.random(). ULIDs generated in the same batch share the same timestamp prefix by design; the 80 random bits keep them unique. All generation happens locally in your browser.