UUID Generator
Runs in your browser. Your files never leave your device.
How we keep your files private
How to use UUID Generator
- Choose how many UUIDs you need.
- Press the refresh button to generate a new set.
- Copy the list.
Common uses
- Creating test data and database keys.
- Generating unique identifiers for files or sessions.
- Filling mock APIs with realistic IDs.
About this tool
Generate random version 4 UUIDs using your browser's cryptographic random source (crypto.randomUUID where available). Choose how many you need, from 1 to 100, and copy them all at once. UUIDs are generated locally and are never logged or stored.
Worked example
A version 4 UUID looks like 3f2b8c1e-9d4a-4b7e-8a65-2c1d0e9f7a43. The 4 at the start of the third group marks the version, and the first character of the fourth group is 8, 9, a or b. There are 122 random bits, so collisions are practically impossible.
Common problems and fixes
- My database wants UUIDs without dashes.
- Strip the dashes: they are only a display convention for the 32 hexadecimal digits.
- A UUID is not a secret.
- UUIDs are identifiers, not passwords or access tokens. Use the password generator for secrets.
- Upper or lower case?
- Both are valid and compare equal. Most systems store lower case.
Next steps
Frequently asked questions
Are UUIDs really unique?
Version 4 UUIDs use 122 random bits, so collisions are astronomically unlikely in practice.
Is this cryptographically secure?
It uses crypto.randomUUID where available, which draws from the browser's secure random source.
Which UUID version is generated?
Version 4 (random).
Are my files uploaded to a server?
No. Everything runs inside your browser on your own device, so your files and text are never sent anywhere.
Is it really free?
Yes. There is no sign-up, no watermark and no limit on how often you use it.
Does it work on my phone?
Yes. It works in any modern browser on phones, tablets and computers. Very large files may be slow on older phones.