UUID Generator
Generate UUID v4 identifiers. Cryptographically random, browser-side only.
Loading...Loading...Loading...Loading...Loading...00000000-0000-0000-0000-000000000000About the UUID Generator
This UUID generator produces random version 4 UUIDs — 36-character identifiers unique enough to use as database keys without coordination. Generate one or hundreds at a time, entirely in your browser.
A UUID generator produces a 128-bit identifier written as 36 characters in five hyphenated groups. Version 4 UUIDs are almost entirely random, which is what lets any machine mint one independently with no central counter and no realistic chance of collision.
That independence is the point. A database sequence requires a round trip and a single authority; a UUID can be created in the browser before a record exists, which makes it the natural choice for distributed systems, offline-first apps and correlation IDs traced across services.
The trade-off is size and ordering. UUIDs are larger than integers and randomly distributed, so using one as a clustered primary key scatters writes across the index. Where insert order matters, a time-sortable variant such as UUID v7 or ULID is the better fit.
How to use the UUID Generator
- Choose how many. Generate a single UUID or a batch.
- Generate. New version 4 UUIDs are produced immediately.
- Regenerate if needed. Generate again for a fresh set — none are stored.
- Copy the values. Take the UUIDs for your keys, fixtures or headers.
UUID Generator features
- Random version 4 UUIDs
- Single or bulk generation
- Standard 36-character hyphenated format
- Uses the browser cryptographic random source
- One-click copy for single or all values
- Runs entirely in your browser
Frequently asked questions
What is a version 4 UUID?
A 128-bit identifier that is almost entirely random, written as 36 characters in five hyphenated groups.
Can two UUIDs ever collide?
In principle yes, in practice no. The random space is large enough that a collision is not a realistic concern for any normal workload.
Why use a UUID instead of an auto-increment ID?
A UUID can be created anywhere with no coordination, which suits distributed systems, offline-first apps and correlation IDs across services.
Are UUIDs good primary keys?
They work, but random ordering scatters index writes. Where insert order matters, consider UUID v7 or ULID instead.
Are the generated UUIDs stored anywhere?
No. They are generated in your browser and never transmitted or logged.