UUID Generator
Generate cryptographically secure UUID v4 identifiers — locally in your browser.
Generated locally using crypto.randomUUID() — no data is sent to any server.
UUID v4 structure explained
UUID v4 uses 122 bits of randomness, providing 5.3 × 10^36 possible values. The probability of two random UUIDs colliding is astronomically small.
Frequently asked questions
What is a UUID?
UUID stands for Universally Unique Identifier. It is a 128-bit label used to uniquely identify objects in computer systems. The standard format is 32 hexadecimal digits grouped as 8-4-4-4-12, separated by hyphens: xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx.
What is the difference between UUID v1 and v4?
UUID v1 is based on the MAC address of the machine and the current timestamp — it can expose your machine identity and generation time. UUID v4 is completely random (122 bits), revealing nothing about the generator. Use v4 for privacy.
Can two UUIDs ever be the same?
Theoretically yes, but practically never. With 2^122 possible v4 UUIDs, generating a billion UUIDs per second for a century would still give you less than a 1-in-a-billion chance of a collision.
Where are UUIDs used?
Database primary keys (instead of sequential integers), distributed system IDs, file names, session tokens, API keys, git commits, Docker container IDs, and anywhere a unique identifier is needed without central coordination.
Is crypto.randomUUID() available in all browsers?
Yes — crypto.randomUUID() is supported in all modern browsers (Chrome 92+, Firefox 95+, Safari 15.4+, Edge 92+). This generator falls back to a crypto.getRandomValues() implementation for older browsers.