What is a UUID?
A UUID (Universally Unique Identifier) is a 128-bit identifier that is virtually guaranteed to be unique across time and systems, with no central coordination required. UUID v4 is fully random, while UUID v7 is time-ordered — it embeds a timestamp, so newly generated IDs sort chronologically. This makes v7 a good fit for database primary keys where index locality matters.
How to use this tool
Pick UUID v4 or v7 and click Generate for a single identifier, or use the Bulk Generator to create up to 1,000 at once. Paste any UUID into the Validator to check whether it is well-formed and which version it is.
Example
A UUID v4 looks like 9b2f1e3a-7c4d-4a1b-8f3e-1234567890ab. The 4 at the start of the third group is the version.
A UUID v7 looks like 01a139bf-b332-75b9-81d3-bcd3cba532f2. Its first 12 hex digits (01a139bfb332) are a Unix timestamp in milliseconds — here 2026-10-14 09:30:26.994 UTC — which is why v7 IDs generated later sort after earlier ones. Pasting either value into the Validator reports Valid UUID v4 or Valid UUID v7.
To seed test data, set the Bulk Generator count to 1000 and copy all IDs at once — one UUID per line.
FAQ
Which version should I use?
Use v4 for general-purpose random IDs. Use v7 when you want IDs that sort by creation time, such as database primary keys.
Are these UUIDs cryptographically secure?
Yes. Generation uses the RFC 9562 compliant uuid library backed by your browser's cryptographically secure random number generator.