Fieldlet

💻 Developer Tools

UUID Generator

Generate one or many random UUID v4 identifiers locally.

Ready to use · Runs in your browser · No signup
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How to use the UUID Generator

Generate RFC 4122-style version 4 UUID values using the browser's cryptographic random-number facilities.

Generate version 4 UUIDs for test data, local identifiers, database keys, and development workflows. Values are created in the browser from cryptographically secure random bytes when the platform supports the standard API.

Input stays in the browser and is not sent to Fieldlet. Do not treat a formatting, encoding, test, or generated value as a substitute for security review.

  1. Choose how many UUIDs you need.
  2. Generate the values locally in your browser.
  3. Copy the complete newline-separated list for use in code, tests, databases, or fixtures.

Last reviewed for accuracy:

Worked examples

Create identifiers for fixtures

Scenario: A developer requests three UUIDs for independent test records.

Result: Three values in the 8-4-4-4-12 hexadecimal layout are returned, each with version and variant bits set appropriately.

Random bytes provide the variable bits while specific positions encode UUID version 4 and the standard variant.

How the result is produced

A UUID is 128 bits. Version 4 leaves most bits random and reserves a small set for the version and variant. The familiar hyphenated text is a representation of those bits, not an encrypted value.

  • Version 4 UUIDs are random identifiers
  • Uniqueness is probabilistic, not a central registry guarantee
  • UUIDs should not be treated as passwords or authorization tokens

References

These primary references document standards or definitions used in the explanation above.

Limitations and common mistakes

  • A UUID can be exposed, guessed from logs, or copied, so it provides no access control by itself.
  • Systems with strict ordering or database locality requirements may prefer another reviewed identifier scheme.

Common questions

Are these sequential?

No. Version 4 UUIDs are random identifiers rather than counters or timestamps.

Can two generated UUIDs ever match?

A collision is theoretically possible but extraordinarily unlikely with secure random version 4 generation. Systems should still enforce uniqueness where correctness requires it.

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