UUID Generator
Generate one or many RFC 4122 v4 UUIDs.
1 – 1000
About UUID Generator
The UUID Generator creates RFC 4122 version 4 UUIDs — the random, collision-resistant identifiers used as primary keys, request ids, correlation ids and trace tokens across modern systems. Generate one or dozens at a time, in lowercase or uppercase, ready to paste into tests, fixtures or API calls.
Generation uses your browser's cryptographically secure random source, entirely offline. Each of the 122 random bits makes a collision practically impossible, which is exactly why v4 UUIDs are safe to mint anywhere without coordination.
How to use
- Choose "How many" UUIDs you need.
- Pick lowercase or uppercase under "Case" to match your system's convention.
- Click "Generate UUID v4" and copy the results from "Generated UUIDs".
Frequently asked questions
Can two generated UUIDs collide?
Theoretically yes, practically no: v4 UUIDs carry 122 random bits, so you would need to generate billions per second for centuries before a collision becomes likely. Treat them as unique.
What is the difference between UUID v4 and v1 or v7?
v4 is purely random. v1 embeds a timestamp and MAC address (a privacy concern), and the newer v7 is time-ordered for database-friendly sorting. For test data and correlation ids, v4 is the safe default.
Does uppercase vs. lowercase matter?
RFC 4122 outputs lowercase and treats comparison as case-insensitive, but real systems sometimes compare as raw strings — a good edge case to test. Generate the case your system stores canonically.