UUID Generator
Generate v4 and v7 UUIDs in bulk — runs entirely in your browser, nothing is sent anywhere.
About
A UUID (Universally Unique Identifier) is a 128-bit value used to identify something — a database row, a request, a file — without a central authority handing out numbers. The chance of two independently generated UUIDs colliding is astronomically small, so systems can mint IDs anywhere — a browser tab, a serverless function, an offline device — and trust they won't clash.
UUIDv4is the version most people mean when they say "UUID": 122 bits of randomness arranged into the standard 8-4-4-4-12 hex format, with fixed version and variant bits. It's fully unpredictable, which is the point — you can't guess the next one from the last one. That matters for things like session tokens or public-facing IDs, where sequential guessing would be a real problem.
UUIDv7, standardized in RFC 9562, trades some of that unpredictability for structure: the first 48 bits are a millisecond-precision Unix timestamp, followed by 74 bits of randomness. Because the timestamp sits first, UUIDs generated later always sort after ones generated earlier — plain string or byte comparison puts them in time order. That matters more than it sounds: database indexes (B-trees especially) store data in key order, and inserting monotonically increasing keys keeps writes clustered at the end of the index instead of scattered across it. Swap a v4 primary key for v7 and you often see measurable gains in insert throughput and cache locality, with almost none of the downside — the timestamp only reveals roughly when a row was created, not what it contains.
Every UUID on this page — v4 or v7 — is generated with crypto.getRandomValues(), the browser's cryptographically secure random number generator. Generation happens entirely on your device; nothing you produce here is transmitted, logged, or stored anywhere, including by us.