UUID & GUID Generator – Bulk Cryptographic Random v4 UUIDs
What is a UUID (Universally Unique Identifier)?
A UUID (Universally Unique Identifier), also known in Microsoft environments as a GUID (Globally Unique Identifier), is a 128-bit label used for computer information. Standardized by RFC 4122, UUIDs enable distributed systems to uniquely identify records, transactions, database rows, and network sessions without requiring a central coordinating authority.
Understanding Version 4 (Random) UUIDs
UUID Version 4 values are generated using cryptographically strong pseudo-random numbers. Out of the 128 total bits:
- 4 bits indicate the version (
0100for Version 4). - 2 bits represent the RFC 4122 variant (
10). - The remaining 122 bits are completely random entropy.
What is the Probability of a UUID Collision?
The total number of possible UUID v4 values is 2122 (approximately 5.3 × 1036, or 53 undecillion). To put this in perspective: if you generated 1 billion UUIDs every second for 100 years, the probability of generating even a single duplicate is less than one in a billion. You can safely generate UUIDs offline across distributed microservices without worrying about ID collisions.
Frequently asked questions
How are these UUIDs generated?
They are generated client-side using your browser's cryptographically secure random number generator (window.crypto.randomUUID / crypto.getRandomValues).
Are UUIDs and GUIDs the same?
Yes. GUID (Globally Unique Identifier) is Microsoft's implementation terminology for RFC 4122 UUIDs. Both follow the 128-bit structure formatted as 32 hexadecimal digits separated by hyphens (8-4-4-4-12).
Can I use these for database primary keys?
Yes. UUID v4 is standard for distributed databases (PostgreSQL, MongoDB, MySQL, Cassandra) where auto-incrementing integers create bottlenecks or reveal transaction volumes.