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UUID Validator
Checks whether a UUID is valid and reports its version and variant, decoding the timestamp from v1, v6 and v7 identifiers.
Developer
Nothing uploaded
No sign-up
Free, unlimited
Paste something on the left to see the result.
In short
UUID Validator is a free online tool on inputtesthub.com that checks whether a UUID is valid and reports its version and variant, decoding the timestamp from v1, v6 and v7 identifiers. It needs no account, no download and no payment, and there is no daily usage limit. Everything is processed inside your own browser, so the data you paste is never uploaded to a server.
How to use the UUID Validator
- Paste your code into the input area.
- Choose the indentation and output options you want.
- Read the formatted result, then copy or download it.
About the UUID Validator
The UUID Validator checks whether a UUID is valid and reports its version and variant, decoding the timestamp from v1, v6 and v7 identifiers. It runs as plain JavaScript inside the page, which means there is no upload step, no queue and no size limit imposed by a server — the only limit is your own device.
What people use it for
- Confirming an id from a log or a URL is a real UUID.
- Finding out whether an identifier leaks a creation time.
- Checking a batch of ids from a database export at once.
Details
| Format | 32 hex digits as 8-4-4-4-12 |
|---|---|
| v4 | Random — the usual choice |
| v7 | Unix time then random, so it sorts |
| v1 and v6 | Encode a time and a MAC address |
| Nil UUID | All zeroes, meaning no value |
The maths behind it
This tool uses the version is the first hex digit of the third group and the variant is the top bits of the fourth. Everything else is payload — random in v4, a timestamp in v1, v6 and v7. Every intermediate value is shown on screen, so the result can be checked by hand.
This validates the format, the version and the variant. It cannot tell you whether the id exists in your system, or whether it came from a good random source — a UUID from a weak generator is structurally perfect and still guessable.
Where this tool stops
The braced, urn:uuid: and unhyphenated forms are accepted and normalised. A Microsoft GUID printed in its little-endian byte order will read as a different UUID here than in the tool that produced it.
Frequently asked questions
Can a UUID be traced back to a computer?
A v1 or v6 one often can. Both encode the creation time and, unless the multicast bit is set, the network card address of the machine that generated it. That is not a flaw — it is how they guarantee uniqueness without coordination — but it makes them a poor choice for a public identifier. v4 and v7 carry no such information.
Should I use v4 or v7 for database keys?
v7, in almost every case. It is just as random and unguessable in its lower bits, but the leading 48 bits are a Unix timestamp, so newly inserted rows land next to each other in the index instead of scattering across it. Random v4 primary keys fragment a B-tree badly, and the write cost shows up as a table grows.
Do I need an account to use the UUID Validator?
There is no cost and no cap. The UUID Validator is not a demo of a paid product, so nothing is held back or watermarked.
Is what I paste into the UUID Validator stored?
No. The UUID Validator runs entirely in your browser using JavaScript. Nothing is transmitted, logged or stored, which you can verify yourself in the Network tab of your browser's developer tools.
What formula does the UUID Validator use?
It uses the version is the first hex digit of the third group and the variant is the top bits of the fourth. Everything else is payload — random in v4, a timestamp in v1, v6 and v7. The full working is printed under the result, so you can follow every step rather than trusting a black box.
What is the UUID Validator used for?
Typical uses: confirming an id from a log or a URL is a real UUID. Finding out whether an identifier leaks a creation time. Checking a batch of ids from a database export at once. It is built for exactly those cases rather than being a general-purpose tool with this bolted on.
Is there anything the UUID Validator cannot do?
The braced, urn:uuid: and unhyphenated forms are accepted and normalised. A Microsoft GUID printed in its little-endian byte order will read as a different UUID here than in the tool that produced it. Knowing where a tool stops being trustworthy matters more than the cases where it works.
What figures does the UUID Validator work from?
Format is 32 hex digits as 8-4-4-4-12. v4 is Random — the usual choice. v7 is Unix time then random, so it sorts. These are printed on the page itself, so you do not have to take them on trust.
Will this work on a tablet?
Yes. The page is responsive and the utility works in Chrome, Safari, Firefox, Edge and Samsung Internet on both Android and iOS. There is no app to install and nothing to sign into.
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