UUID generator (v4 and v7)
Make random UUIDs (v4) or time-ordered UUIDs (v7) with your browser's secure random generator, up to 500 at a time. Paste a UUID below to see its version and when it was made.
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How it works
A UUID is a 128-bit identifier. Version 4 is completely random (122 random bits), so it reveals nothing. Version 7, standardised in RFC 9562 in 2024, starts with the time in milliseconds, so new IDs sort in order, which keeps database indexes fast.
All IDs are made with your browser's secure random generator. The checker reads any UUID's version and variant, and shows when time-based ones (v1, v6, v7) were made.
Questions people ask
UUID v4 or v7?
Use v7 for database keys and anything you want sorted by creation time. Use v4 when the ID shouldn't reveal when it was made.
Can two UUIDs be the same?
In practice, no. With v4 you'd need to generate billions per second for many years before a collision becomes likely.
Are UUIDs safe to use as secret tokens?
Random v4 UUIDs are hard to guess, but they aren't designed as secrets. Time-based versions are partly predictable and v1 can contain a network card's MAC address. Use a dedicated random token for secrets.
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