UUID Validator Online
Confirm a UUID is well formed and find out which version it is, so you know whether it is random, time-based or something that only looks like a UUID.
Browser tool
UUIDs
Paste one UUID or a list (one per line). Canonical, compact, braced and URN forms are recognised.
About UUID Validator
A string of hexadecimal with hyphens in roughly the right places is not necessarily a UUID, and even a valid one may not be the kind you expect. This confirms the format and reports the version and variant, which is what actually tells you how it was generated. No account, no fee, no upload, and free to use. The check runs online inside the browser you are reading this in.
How to use UUID Validator
- Paste one or manyA single value, or a list to check in bulk.
- Read the versionVersion 4 is random. Version 1 and 6 encode a timestamp. Version 7 is time-ordered and increasingly the default for database keys because it sorts.
- Export the reportA CSV of results, if you are checking a column from a database.
What version and variant mean
A UUID carries its own metadata. Four bits state the version — how it was generated — and a few more state the variant, which says whose layout rules it follows. A value can be perfectly formatted and still report a version that does not exist, which usually means it was assembled by hand or by something that did not follow the specification.
What it does not do
- Valid does not mean unique, and it certainly does not mean it exists in your system. This checks the shape and the metadata, not whether anything is identified by it.
- A version 4 UUID is random but not a secret. It is not unguessable enough to use as a security token on its own.
UUID Validator: questions people ask
- Is a UUID safe to use as a password reset token?
- Not on its own. Version 4 uses a random number generator that many implementations do not promise is cryptographically secure, and versions 1 and 6 encode a timestamp and sometimes a MAC address. Use a token from a CSPRNG for anything security-bearing.
- Which version should I generate?
- Version 4 for a general identifier. Version 7 when the identifier is a database primary key, because it is time-ordered and therefore does not fragment an index the way random values do.
- What regular expression checks a UUID?
- The canonical 8-4-4-4-12 form matches ^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}$ with the case-insensitive flag. A regex only checks the shape; the validator also reads the version and variant digits, which a shape check cannot tell you.
Questions about ToolsVerse itself — privacy, cost, what happens to your files — are answered in the frequently asked questions.
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