UUID v4 Generator Online — Create Random UUIDs
Generate cryptographically secure UUID v4 identifiers locally in your browser. Create multiple copy-ready IDs for databases, APIs, tests and fixtures.
Generate cryptographically secure UUID v4 values locally.
About this tool
The UUID generator creates version 4 universally unique identifiers from cryptographically secure browser randomness. UUIDs are useful when independent systems need identifiers without coordinating a central numeric sequence.
How to use
- Select the generate button to create a fresh group of UUID v4 values.
- Copy one or more identifiers from the result.
- Use them as test IDs, database keys or request identifiers where UUID v4 is accepted.
Features
- Uses the browser cryptography API for secure randomness.
- Produces standard lowercase UUID v4 strings.
- Generates multiple identifiers at once without a network request.
Common use cases
- Create identifiers for database rows and distributed records.
- Prepare stable IDs for API fixtures and automated tests.
- Generate correlation or request IDs during development.
Common issues and tips
- UUIDs are identifiers, not passwords, authentication tokens or proof that a record is trustworthy.
- Store UUIDs consistently as native UUID values or normalized lowercase strings.
Privacy
UUIDs are generated locally with your browser cryptography API and are not sent to Tools12345.
Frequently asked questions
Are UUID v4 values guaranteed to be unique?
No finite random identifier has an absolute guarantee, but a correctly generated UUID v4 has an extremely low collision probability.
Can I use a UUID as a secret token?
A UUID identifies something; it is not automatically suitable as an authentication secret. Use purpose-built secure tokens for authorization.
Why are some characters fixed in UUID v4?
The version and variant bits have defined values, while the remaining bits are random.