UUID Generator
Cryptographically random UUID v4 values, generated in your browser.
What a UUID v4 is
A UUID (Universally Unique Identifier), sometimes called a GUID, is a 128-bit value written as 32 hexadecimal digits in five hyphen-separated groups. Version 4 is the random variant: 122 of its bits come from a random source, with the remaining six fixed to mark the version and variant.
This generator uses the browser's crypto API, so the values are cryptographically random rather than derived from Math.random().
Frequently asked questions
Can two UUIDs ever collide?
In theory yes, in practice no. With 122 random bits you would need to generate billions of UUIDs per second for decades before a collision became likely. For application identifiers the risk is negligible.
Should I use a UUID as a database primary key?
It works and avoids coordinating IDs across systems, but random UUIDs scatter inserts across a B-tree index, which can hurt write performance and bloat the index on large tables. Many teams use UUIDv7 or an ordered variant when insert order matters, or keep an internal integer key alongside a public UUID.
What is the difference between UUID and GUID?
Nothing meaningful. GUID is Microsoft's name for the same 128-bit standard; the formats are interchangeable.
Are these generated on your server?
No. Every value is produced locally in your browser and never transmitted, so you can safely use them in production.