How the uuid generator works
A UUID is a 128-bit identifier commonly used when systems need independently generated record IDs without coordinating a central sequence. This page creates version 4 UUIDs using the browser's native randomUUID function and can return up to 100 values at once.
Method and behaviour
Version 4 UUIDs are mostly random bits with fixed version and variant fields. The familiar text form contains 32 hexadecimal digits separated into 8-4-4-4-12 groups. The first character of the third group is 4, identifying the version.
The browser provides the randomness and formatting. UUIDs make collisions extremely unlikely for ordinary use, but they do not prove who created a record, when it was created, or that its contents are trustworthy.
Worked example
A value shaped like 2f1c8a90-6b72-4d51-a9ee-783c294f1012 is a version 4 UUID because the third group begins with 4. The exact value shown here is an explanatory example, not a reserved identifier.
Useful for
- Assigning IDs to records created offline
- Preparing fixtures and sample data
- Naming files or jobs without a central counter
- Creating correlation identifiers for non-secret events
Important limitations
- A UUID is an identifier, not a password or authentication token
- Version 4 does not encode a creation time
- A downstream system may require another UUID version or storage format
Questions specific to this tool
Are UUIDs guaranteed never to collide?
No finite random space provides an absolute guarantee, but version 4's space makes accidental collision extraordinarily unlikely at ordinary scales.
Can I decode the creation date?
No. A version 4 UUID is random and does not carry a timestamp.
Should I use a UUID as a secret token?
Not by assumption. Identifiers and security tokens have different threat models; use a purpose-built token design for authentication or authorization.
Reviewed by: UtilityTrove editorial team · Last reviewed: August 15, 2026 · Tool version 1.0.0