UUID Generator v4
Generate dozens of random globally unique identifiers.
The End of Repeated IDs
Distributed systems of the new world hate old databases where the ID identifier grew gradually and repetitively for each customer table the database opened (for example, João is ID 1 and Marcos is ID 2). At any moment in a huge, parallel cloud system (Cloud Computing), these IDs would collide in a transaction with catastrophic dangers.
Mathematically Unlikely
If you need to seed fake data for tests (Seed Factory) or manually populate the columns of your new PostgreSQL, click generate! Version 4 will create for you a pseudo-random key with such brutal entropy that generating the same UUID string twice should not occur until the end of the solar universe.