Support: UUID Generator

Tell us what happened. Include which page you were on and what you expected to see. Most answers go out within a business day.

Common questions

What is the difference between UUID v4 and v7?

Version 4 is entirely random. Version 7 begins with the time it was made, to the millisecond, then random bits, so ids sort in the order they were created, which keeps database indexes compact and makes rows easy to order. Use v7 for new database keys and v4 where no ordering is wanted.

Are these UUIDs unique?

Version 4 has 122 random bits from the browser's cryptographic random source; the chance of any two ever being the same is so small it is treated as zero. Version 7 adds the time, and version 5 is unique for a given namespace and name by construction.

What is a GUID?

The same thing as a UUID; GUID is Microsoft's name for it, often shown in upper case and braces. Tick Upper case and In braces for that form.

How do I make the same UUID every time for a name?

Choose version 5, pick the namespace (URL for web addresses, DNS for domain names, or your own UUID) and type the name. The result is computed with SHA-1 and will be identical on any system that follows the standard.

Can I generate many at once?

Yes, up to 1,000 per click, one per line, or quoted and comma separated for pasting into code or a query.

Is there a limit to how many I can make?

No. Generate as many sets as you like; nothing is counted against you and nothing is stored.

Are the UUIDs sent anywhere or logged?

No. They are made by code in your browser from its own random source, and they exist only on the page until you copy them.

Is it free?

Yes, completely free, with no sign-up.