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UUID generator

Create one or a thousand UUIDs, random (v4) or time-ordered (v7), format them your way, and check the version of any UUID.

Your data never leaves your browser

Paste API responses and tokens safely: nothing is sent anywhere.

Version

Fully random. The usual choice for ids.

Generated UUIDs

Check a UUID

Paste a UUID to see its version.

Next, try one of these tools

How to use

  1. 1Choose version 4 or 7 and how many you need.
  2. 2Pick uppercase, hyphens and braces, then press Generate.
  3. 3Copy all of them or download a text file.
  4. 4To check a UUID, paste it in the checker to see its version and variant.
A list of generated UUIDs with a copy button

Common uses

  • Database keys

    Generate a batch of v7 ids to seed rows that should sort by creation time.

  • Test data

    Make a hundred random ids for fixtures, mock APIs and unit tests.

  • Correlation ids

    Create request ids to trace a call across several services.

  • Checking an unknown id

    Paste an id from a log to see which version and variant it is, and when a v7 was made.

Tips and limits

  • Random v4 ids are not sortable. Choose v7 when you want creation order, for example for an indexed primary key.
  • In a batch made within one millisecond, v7 ids still sort in creation order, because a small counter breaks ties.
  • A v7 id reveals its creation time. Do not use it where that would be sensitive.
  • Ids are created with your browser’s cryptographic random generator, not Math.random.

Random or time-ordered UUIDs, one or a thousand

A UUID is a 128-bit identifier written as 32 hexadecimal digits, designed so that two systems can create ids without coordinating and still almost never collide. Version 4 is fully random and is the usual choice. Version 7, defined in RFC 9562, starts with a millisecond timestamp, so ids created later sort after earlier ones; that keeps database indexes compact and makes ids useful as sortable keys. Generate from 1 to 1000 at a time, switch to uppercase, remove hyphens or wrap them in braces, then copy all or download a text file.

The checker reads any UUID you paste, with or without hyphens or braces, and tells you its version and variant, and for version 7 the time it embeds. UUIDs are often used as a token’s jti claim, so they pair naturally with the JWT decoder, and to turn one into a fixed fingerprint you can use the hash generator. Structured data containing ids is easier to read after the JSON formatter, and what a JWT is explains where a unique id fits in a token.

Step-by-step guides

Frequently asked questions

What is a UUID?

A 128-bit identifier, written like f47ac10b-58cc-4372-a567-0e02b2c3d479, that is unique for practical purposes without a central authority.

What is the difference between UUID v4 and v7?

v4 is fully random. v7 begins with a timestamp, so newer ids sort after older ones, which suits database keys.

How do I generate many UUIDs?

Set the number, up to 1000, press Generate, and copy all or download them as a text file.

Is a UUID the same as a GUID?

Yes. GUID is Microsoft’s name for the same thing. Some systems write them uppercase or in braces, which you can choose here.

Can two UUIDs be the same?

It is astronomically unlikely for properly generated v4 or v7 ids, which is why they are used without coordination.