UUID Generator
Generate one or more cryptographically random UUID v4 identifiers. Uses your browser's built-in crypto API — results are never sent to a server.
Quantity
Click Generate to create UUIDs.
What is a UUID?
A Universally Unique Identifier (UUID) is a 128-bit label defined in RFC 4122. UUIDs are typically written as 32 hexadecimal digits in five groups separated by hyphens: xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx.
UUID version 4
Version 4 UUIDs are randomly generated. Two specific bits encode the version (4) and variant (RFC 4122). The remaining 122 bits are cryptographically random, giving a collision probability so low it is negligible for all practical purposes.
Why not Math.random()?
Math.random() produces pseudo-random numbers that are predictable given the internal state. This tool uses crypto.randomUUID() (and crypto.getRandomValues() as a fallback) — both are cryptographically secure and suitable for generating IDs used in databases, file names, and API resources.
Common use cases
- Primary keys in databases (especially distributed systems)
- Unique filenames for uploaded assets
- Idempotency keys for API requests
- Session or correlation identifiers
Frequently Asked Questions
Are UUID v4 identifiers cryptographically secure?
Yes. Utility Hub utilizes the browser's native crypto.randomUUID() and crypto.getRandomValues() CSPRNG engines. We never use predictable Math.random().
What is the collision probability of UUID v4?
UUID v4 contains 122 bits of true entropy (3.4 × 10^38 combinations). Generating 1 billion UUIDs every second for over 80 years yields less than a 50% probability of an accidental collision.
What is the difference between UUID v4 and UUID v7?
UUID v4 is entirely random, perfect for public tokens and security IDs. UUID v7 embeds a 48-bit timestamp prefix, making it optimal for database indexing and B-tree cache locality.
Are generated UUIDs saved or logged on a server?
No. All identifiers are generated purely inside your browser memory. They are never transmitted or logged.