UUID Generator
Generate RFC-4122 UUIDs — versions 1, 4 and 7 plus the nil UUID — in bulk, with formatting options and one-click copy or download.
Random — the most common UUID, generated from secure random bytes.
About the UUID Generator
Updated June 2026 · 100% client-side — your data never leaves your browser.
A UUID (universally unique identifier) is a 128-bit value used to label data without a central authority, virtually guaranteeing uniqueness across systems. Bytewrench generates RFC-4122 version 4 (random) UUIDs instantly, with the option to create many at once for seeding databases or test fixtures.
Generation uses the browser's cryptographically secure random source, and nothing is sent over the network.
See also: Hash generator, Password generator
Create random RFC-4122 v4 identifiers suitable for keys and references.
Produce a batch of UUIDs at once and copy them all in one click.
Backed by the browser's secure random generator for strong uniqueness.
Generate as many IDs as you need with no server round-trip.
Frequently asked questions
What's the difference between UUID v4 and v7?
v4 is fully random, so values are unordered — great for unguessability but poor for database index locality. v7 embeds a Unix millisecond timestamp in the high bits followed by random data, so IDs sort roughly by creation time, which is much friendlier for primary keys and B-tree indexes. This tool generates v4.
Are UUIDs guaranteed to be unique?
Not literally guaranteed, but for random v4 UUIDs the collision probability is astronomically small — you'd need to generate billions per second for many years before a duplicate became likely. In practice they're treated as unique without coordination.
UUID vs nanoid — which should I use?
UUIDs are 128 bits, standardized (RFC 4122) and recognized everywhere. nanoid is shorter and URL-friendly by default with a configurable alphabet, which is nice for public-facing IDs. Use UUID when you need an interoperable standard; nanoid when compactness in URLs matters more.
Is UUID v4 random and safe to use as a token?
v4 UUIDs use 122 bits of randomness, which is plenty of entropy to be unguessable when generated from a cryptographically secure source like this tool. They're fine as opaque identifiers, though for security tokens many teams still prefer a purpose-built secret with documented entropy.
Are the UUIDs generated on a server?
No. They are created locally in your browser from a cryptographically secure random source, so they're never logged or transmitted.