UUID v4 Generator

What is a UUID?

A UUID (Universally Unique Identifier) is a 128-bit value used to uniquely identify information across distributed systems without needing a central coordinator. The format is standardized in RFC 9562 (formerly RFC 4122) and is typically displayed as 32 hexadecimal digits in five hyphen-separated groups, for example f47ac10b-58cc-4372-a567-0e02b2c3d479.

UUID v4 generator online — bulk generation

UUID v4 values are generated almost entirely from random data — 122 random bits plus 6 fixed version/variant bits. With 2¹²²possible values, collisions are astronomically unlikely. This bulk UUID generator pulls randomness from your browser's crypto.getRandomValues via the uuid package, so generated IDs are safe to use as database primary keys, session tokens, file names, or correlation IDs. You can produce up to 50 at a time, with optional uppercase and no-dash output.

UUID vs ULID — when to prefer ULID

UUID v4 is unbeatable when you need maximum entropy and zero metadata leakage. Where it falls short is sortability: random UUIDs scatter across B-tree indexes, hurting insert performance at scale and making time-ordered queries awkward. ULID (and its cousin UUID v7) embed a millisecond timestamp prefix, so IDs are lexicographically sortable by creation time and behave much better as primary keys in busy databases. Pick UUID v4 for stateless tokens and external identifiers; pick ULID or UUID v7 when the ID is also a database key.