UUID Generator — Generate Random UUID v4 Online Free
Generate cryptographically random UUID v4 identifiers in seconds. Useful for primary keys, correlation IDs, session tokens, and any place you need a unique identifier. Choose how many UUIDs you need, toggle uppercase, and copy them all at once. Everything runs locally in your browser — nothing is sent to a server.
How it works
- 1 Set the quantity Enter how many UUIDs you want to generate — from 1 up to 100 at a time. The default is 1.
- 2 Click Generate Hit the Generate button and your UUIDs appear instantly. Each one is a fully random RFC 4122 version 4 UUID.
- 3 Copy one or all Click Copy next to any individual UUID, or use Copy All to copy the entire list as newline-separated text, ready to paste into a file or database seed script.
Your data stays private
All processing happens entirely in your browser. No files, text, or data are ever sent to our servers. You can disconnect from the internet and this tool will still work.
Frequently asked questions
- What is a UUID v4?
- UUID v4 is a Universally Unique Identifier generated from random (or pseudo-random) numbers. It follows the format xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx where x is a random hex digit and y is one of 8, 9, a, or b. The chance of a collision between two randomly generated UUIDs is astronomically small.
- Are these UUIDs safe to use as database primary keys?
- Yes. UUID v4 is widely used as a primary key in relational and NoSQL databases. The collision probability is negligible — you would need to generate over a billion UUIDs per second for 85 years to have even a 50% chance of one collision.
- What is the difference between UUID v1 and v4?
- UUID v1 is based on the current timestamp and the MAC address of the machine, which means it encodes location and time information. UUID v4 is purely random and reveals nothing about when or where it was generated — making it more privacy-friendly and suitable for most modern applications.
- Can I use UUIDs as URL slugs?
- Technically yes, but they make long and unreadable URLs. If readability matters, consider a shorter random ID like nanoid instead. UUIDs work well as internal resource identifiers (API endpoints, database IDs) where humans rarely see the raw value.
- Does this tool send my UUIDs anywhere?
- No. UUID generation runs entirely in JavaScript inside your browser. No data is sent to any server. You can load the page, disconnect from the internet, and the tool still works perfectly.