โ Frequently Asked Questions โ UUID Generator
What is a UUID?
UUID stands for Universally Unique Identifier. It's a 128-bit label used to uniquely identify information in computer systems. A UUID looks like: 550e8400-e29b-41d4-a716-446655440000. They are used as primary keys in databases, session IDs, API keys, and anywhere a unique identifier is needed without a central authority.
What is the difference between UUID v1 and v4?
UUID v1 is generated using the current timestamp and the device's MAC address, making it sortable by creation time but potentially exposing machine information. UUID v4 is randomly generated using a cryptographically secure random number generator, making it the safer and more widely used choice for most applications.
Are generated UUIDs truly unique?
UUID v4 has 122 bits of randomness, giving approximately 5.3 ร 10^36 possible values. The probability of generating the same UUID twice is astronomically small โ less than 1 in a billion even after generating trillions of UUIDs. For all practical purposes, they are unique.
Can I use UUID as a database primary key?
Yes โ UUID is commonly used as a primary key, especially in distributed systems where auto-increment integers would conflict across multiple servers. UUID v4 is preferred for security. UUID v1 or v7 (time-ordered) are better for databases that benefit from sequential ordering, as random UUIDs can cause index fragmentation in large tables.