UUID v4 Generator
Generate v4 UUIDs using the browser's cryptographic random source.
Generate cryptographically random UUID v4 identifiers. Free, offline, runs in your browser. Read more Show less
What is a UUID?
A UUID (Universally Unique Identifier) is a 128-bit value displayed as 32 hexadecimal digits in five groups: 8-4-4-4-12. Version 4 UUIDs are generated from random or pseudo-random numbers. The chance of collision is negligible: you would need to generate 2.7 x 10^18 UUIDs before reaching a 50% probability of one collision.
How to use
Choose how many UUIDs to generate (1 to 1000) and click Generate. Copy individual values or the whole list. UUIDs are generated using the browser cryptographic random source (crypto.randomUUID()), which is suitable for identifiers in production systems.
FAQ
Why v4 and not v1 or v7?
v4 is fully random and requires no coordination. v1 and v7 embed a timestamp and are sortable, which is useful for database primary keys. Those versions need a machine identifier or clock, which is why they have their own generators (coming soon).
Are these UUIDs safe to use as primary keys?
Yes, if your storage engine can handle random writes. For databases that prefer sequential inserts, prefer UUID v7.
Uppercase vs lowercase?
Both are valid. RFC 4122 recommends lowercase. Some legacy systems require uppercase; use the toggle.