UUID Generator
Generate random UUID v4 identifiers instantly. Perfect for databases, APIs, and unique reference numbers.
Single UUID
Generate Multiple UUIDs
Use Cases
- Database primary keys and foreign keys
- API request/response tracking
- Session and user identifiers
- Distributed system unique references
- Transaction IDs and order numbers
Why random IDs beat sequential ones
Counting 1, 2, 3 for your records seems simpler, but it leaks information (anyone can guess the next ID) and falls apart the moment two systems try to create records at once. A UUID sidesteps both problems: it's a 128-bit value random enough that you can generate one anywhere, on any machine, and trust it won't collide with another.
Where UUIDs earn their keep
You'll reach for them as database primary keys, as identifiers in APIs and distributed systems, for naming files or tracking events, and anywhere you need a unique handle without asking a central server for the next number. Generate one at a time, or batch up to a hundred at once — all created in your browser.
Frequently Asked Questions
Is a UUID truly unique?
In practice, yes. While UUID v4 is randomly generated and theoretically could collide, the probability is so vanishingly small that it is treated as unique for all practical purposes. The chance of a collision is lower than 1 in a trillion trillion.
What is the difference between UUID v1 and UUID v4?
UUID v1 is generated from the current timestamp and the MAC address of the machine, making it traceable to a specific device and time. UUID v4 is purely random with no embedded information. For privacy and security reasons, v4 is preferred for most applications.
Can I use UUID as a database primary key?
Yes. UUIDs are excellent primary keys for distributed databases where multiple servers insert records simultaneously. Unlike auto-increment integers, UUIDs avoid ID conflicts across shards. However, random UUID v4 can cause index fragmentation in B-tree indexes — consider UUID v7 (time-ordered) for better database performance.