How to Use
- Select UUID version (v4 for random, v1 for time-based).
- Adjust options: count, case, dash format.
- Click Generate to create UUIDs instantly.
- Click the copy icon next to any UUID to copy it.
- Use Validate or Parse to check existing UUIDs.
FAQ
What is a UUID and why is it used?
A UUID (Universally Unique Identifier) is a 128-bit identifier used to uniquely identify information in computer systems. UUIDs are commonly used as database primary keys, session tokens, API keys, and for distributed systems where unique IDs must be generated without coordination.
What is the difference between UUID v1 and v4?
UUID v1 is time-based, generated from the current timestamp and a node identifier, making it sortable by creation time. UUID v4 is randomly generated using cryptographic random numbers, offering better privacy since it doesn't reveal creation time or machine identity.
Are UUIDs truly unique?
While not mathematically guaranteed to be unique, the probability of generating a duplicate UUID v4 is astronomically low. You would need to generate about 2.71 quintillion UUIDs to have a 50% chance of a single collision, making them practically unique for all real-world applications.
What is a GUID and how is it different from a UUID?
GUID (Globally Unique Identifier) is Microsoft's implementation of UUID. They are functionally identical and follow the same RFC 4122 standard. The terms are often used interchangeably, though GUID is more common in Microsoft ecosystems and UUID in other contexts.
How many UUIDs can be generated before a collision?
For UUID v4, the 122 random bits provide approximately 5.3 x 10^36 possible values. According to the birthday paradox, you would need to generate about 2.71 x 10^18 (2.71 quintillion) UUIDs to have a 50% probability of finding one collision. In practice, collisions are essentially impossible.