UUID v4 Generator
Generate cryptographically random UUID v4 identifiers. Generate 1–100 at once in lowercase or uppercase format.
Generate UUID v4
About UUID v4
UUID v4 (Universally Unique Identifier version 4) is a 128-bit random identifier formatted as xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx. The probability of collision is astronomically low — making them safe to use as primary keys, request IDs, or any unique identifier without coordination between systems.
Generated using the browser's crypto.randomUUID() API — cryptographically random, never leaves your device.
What is a UUID v4?
A UUID (Universally Unique Identifier) v4 is a 128-bit random identifier formatted as 8-4-4-4-12 hexadecimal digits. It is used as primary keys in databases, file names, session tokens, and anywhere a unique ID is needed without a central authority.
How to use
- Set how many UUIDs to generate (1–100).
- Choose lowercase or uppercase.
- Click Generate.
- Copy individual UUIDs or use Copy all.
UUIDs are generated using the browser's crypto.randomUUID() or crypto.getRandomValues() — nothing is sent to any server.
Frequently Asked Questions
- Are UUID v4s unique?
- Statistically yes. With 2^122 possible values, the probability of a collision is astronomically small — for all practical purposes they are unique.
- What is the difference between UUID v1 and v4?
- v1 is time-based and includes the MAC address. v4 is random. v4 is preferred for most use cases because it does not expose hardware or timing information.