// generate RFC 4122 v4 and v7 UUIDs with crypto.getRandomValues — entirely in your browser
click generate
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Bulk quantity
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Generated: 0
About This UUID Generator
This free UUID generator creates RFC 4122-compliant version 4 (fully random) and version 7 (time-ordered) UUIDs using your browser's cryptographically secure random number generator (crypto.getRandomValues), not the weaker Math.random(). Generate a single UUID for quick copy-paste, or a bulk list of up to 100 at once. Optional formatting renders uppercase hex, strips hyphens, or wraps the value in braces for GUID-style output. Works entirely in your browser — nothing you generate is ever sent to a server.
Common uses: primary keys for a new database table, unique IDs for test fixtures or seed data, session or request identifiers, or placeholder GUIDs for a Windows config file or API request.
Frequently Asked Questions
What is a UUID?+
A UUID (Universally Unique Identifier), also called a GUID, is a 128-bit value written as 32 hex digits in the form 8-4-4-4-12, e.g. 550e8400-e29b-41d4-a716-446655440000. It's used to identify records, sessions, or resources without a central authority handing out IDs.
What's the difference between UUID v4 and v7?+
Version 4 is fully random — 122 random bits give effectively zero chance of collision, but the values sort in no particular order. Version 7 embeds a millisecond Unix timestamp in the first 48 bits followed by random bits, so UUIDs generated later always sort after earlier ones — useful as database primary keys where insert order matters for index performance.
Are these UUIDs guaranteed to be unique?+
They're generated with the Web Crypto API's crypto.getRandomValues(), a cryptographically secure random source. With 122 random bits (v4) or 74 random bits (v7), the probability of ever generating a duplicate is astronomically small — far lower than hardware failure rates.
Can I generate multiple UUIDs at once?+
Yes. Use the bulk section to generate up to 100 UUIDs at a time, one per line, then copy the whole list with a single click — handy for seeding test data or database fixtures.
What do the uppercase, no hyphens, and braces options do?+
Uppercase renders hex digits as A-F instead of a-f. No hyphens strips the dashes to a plain 32-character hex string. Braces wraps the value in curly brackets, the format Microsoft tools and some Windows APIs expect for a GUID.
Does this tool send anything to a server?+
No. Every UUID is generated entirely in your browser using JavaScript's Web Crypto API. Nothing is sent anywhere, logged, or stored — refresh the page and it's gone.