UUID Generator (v4)
Generate random version-4 UUIDs in bulk, with formatting options. They're created with your browser's secure random generator — nothing is uploaded.
New to this? Read the UUID Generator guide →
How to use the UUID generator
- Set how many you need (generate one, or a whole batch at once).
- Optionally switch to uppercase, or strip the dashes for systems that want a compact 32-character form.
- Press generate and copy. Every value uses your browser's cryptographic random source, so nothing is produced on or sent to a server.
What a UUID is
A UUID is a 128-bit identifier, written as 32 hex digits in five dash-separated groups. This tool produces version 4 UUIDs, which fill almost all of those bits with randomness. The space is so large that collisions are astronomically unlikely, which is what lets any machine mint one independently with no central coordinator.
v4 vs. other versions
v4 (random) is the right default and the only thing most code needs: it reveals nothing about when or where it was made. If you are choosing IDs for a database primary key, a time-ordered v7 keeps inserts index-friendly. Two companion reads: the UUID versions explained (what v1 through v8 are for) and UUID v4 vs. v7 for database IDs.
Common uses
- Primary keys and foreign keys you can generate before a row is saved.
- Idempotency keys for API requests, so a retry is not processed twice.
- Correlation / trace IDs that tie log lines together across services.
- Unique filenames, upload tokens and test fixtures.
Where you'd use this
Generating identifiers that will not collide across machines: database keys, idempotency keys on payment requests, correlation IDs threaded through logs, and object names in storage.
For example: A payment form needs an idempotency key so a double-tapped submit button does not charge twice. A v4 UUID generated client-side means the retry carries the same key and the second request is recognised as a duplicate.
Frequently asked questions
What kind of UUIDs does it generate?
Random version-4 UUIDs — 128-bit identifiers with effectively zero chance of collision, suitable for database keys, request IDs and more.
Are these UUIDs safe to use as unique IDs?
Yes. v4 UUIDs are generated from cryptographically strong randomness, so duplicates are astronomically unlikely across systems and time.
Are the UUIDs generated on a server?
No. They are generated in your browser using the platform’s secure random source, so the values are never transmitted.