UUID generator
Generate random version 4 UUIDs, one or a hundred at a time, straight from your browser's cryptographic random source. Copy the whole list with one click; nothing is generated on or sent to a server.
Text is processed by your own browser and never leaves your device: this page has no server to send it to.
How it works
Sixteen random bytes come from the browser's crypto.getRandomValues, then two nibbles are fixed as the RFC 4122 markers: the version nibble to 4 and the variant bits to 10. The remaining 122 bits are random, which is where the collision resistance comes from.
Frequently asked questions
Can two generated UUIDs collide?
In theory yes, in practice no: with 122 random bits you would need to generate billions per second for centuries before a collision becomes likely. Treat them as unique.
Are these UUIDs predictable?
No. The bytes come from the browser's cryptographically secure generator, not a seeded pseudo-random function, so previous outputs reveal nothing about the next one.
What is the difference between v4 and v7?
v4 is fully random; v7 embeds a timestamp so rows sort by creation time, which databases like for index locality. For identifiers in URLs and APIs, v4 remains the safe default.