uuid generator

Online UUID Generator

Generate random v4 or time-ordered v7 UUIDs in your browser using the Web Crypto API. Pick a quantity, format, and copy.

v4 vs v7 in one paragraph

v4UUIDs are 122 bits of cryptographic randomness, the collision probability is astronomically low, and they're the safe default for most applications. v7UUIDs put a 48-bit millisecond timestamp at the start and fill the rest with random bits, so they sort chronologically. That's valuable when the UUID is a database primary key because inserts stay contiguous in the index instead of scattering random pages, which noticeably improves write throughput and index locality on hot tables.

Where the randomness comes from

All generation happens locally in your browser. The tool calls crypto.randomUUID() for v4 when the runtime supports it and falls back to crypto.getRandomValues() otherwise; v7 always uses getRandomValues() for the random bits. Nothing is derived from your device, IP, or account, and nothing is sent to a server.

Related: hash generator, random number generator, and password generator for other in-browser crypto primitives.

AIExplain UUIDs

Frequently asked

What is a UUID?
A UUID (Universally Unique Identifier) is a 128-bit value written as 32 hexadecimal characters with four dashes, for example 550e8400-e29b-41d4-a716-446655440000. Because the space is so wide, two independently generated UUIDs are effectively guaranteed to be unique, no central authority or coordination needed.
Should I use v4 or v7?
v4 is fully random and is the safe default for most applications. v7 embeds a millisecond timestamp in the first 48 bits so values sort chronologically, which is friendlier as a database primary key because writes stay contiguous in the index instead of scattering.
Are the generated UUIDs cryptographically random?
Yes. The generator uses the browser's Web Crypto API, crypto.randomUUID() for v4 when available, and crypto.getRandomValues() for v7. Nothing about the UUID is derived from your device, IP, or account.
Is anything sent to a server?
No. Every UUID is generated locally in your browser. No request is made and no value is logged anywhere.