Tool 007 / dev / free / runs locally
UUID Generator
Generate cryptographically random version 4 UUIDs, one or many at a time, and copy them with a click. The values come from your browser secure random source, so they are never generated on a server or logged anywhere.
UUIDs will appear here.How it works
This generator creates version 4 UUIDs, the random kind. A v4 UUID is a 128-bit identifier shown as 32 hexadecimal digits in five hyphen-separated groups (8-4-4-4-12), where 122 of those bits are random and a few fixed bits mark it as version 4. It uses crypto.randomUUID where available and falls back to crypto.getRandomValues, both backed by the browser's secure random source.
Version 4 UUIDs are designed so two independently generated values almost never collide. With 122 random bits the space is so large that you could generate billions and still have a vanishingly small chance of a duplicate, which is why they are the default choice for primary keys, request IDs, and idempotency tokens when you do not have a central authority handing out IDs.
You can generate from 1 to 100 at once and copy them all as newline-separated text. Generation is local and instant; refreshing the page makes a brand new batch.
How to use it
- Drag the slider to choose how many UUIDs you want (1 to 100).
- Click Generate to produce the batch.
- Review the list in the output box.
- Click Copy all to copy every UUID, one per line.
Worked examples
Input: Generate 1
Output: 3f2504e0-4f89-41d3-9a0c-0305e82c3301
The 13th character is always 4 (the version) and the 17th is 8, 9, a, or b (the variant).
Input: Generate 5
Output: Five distinct UUIDs, each on its own line, ready to paste as seed data or test IDs.
Copy all joins them with newlines.
Edge cases and limits
- These are version 4 (random) UUIDs only. If you need time-ordered IDs (v1 or v7) for database index locality, this tool does not produce them.
- v4 UUIDs are not sortable by creation time, because they contain no timestamp.
- The cap is 100 per batch to keep the output readable; for bulk seeding, generate several batches.
Common mistakes
- Treating a UUID as a secret or security token. It is unguessable enough to be hard to enumerate, but it is not authentication on its own.
- Storing UUIDs as text when your database has a native uuid type that is half the size and faster to index.
- Assuming v4 UUIDs sort chronologically. They do not; use a created-at column for ordering.
Frequently asked questions
What is a version 4 UUID?+
A version 4 UUID is a 128-bit identifier whose bits are mostly random. It is the most common UUID type because it needs no central coordination and has an extremely low collision chance.
Are these UUIDs safe to use as database keys?+
Yes. Version 4 UUIDs are generated from a secure random source and are suitable as primary keys, request IDs, and file names. The chance of two colliding is negligible in practice.
Are the UUIDs generated on a server?+
No. They are produced locally using the browser crypto API. Nothing is requested from or sent to a server, so the values stay private to your device.
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