Where does the randomness come from?

From the browser's crypto.randomUUID, which draws on a cryptographically secure generator. If a browser lacks that function, the page fills sixteen random bytes with crypto.getRandomValues and sets the version and variant bits itself.

Can two generated UUIDs be the same?

In theory yes, in practice almost never: a version 4 UUID has 122 random bits. This page does not check values against your database, so keep a unique constraint on the column as a safety net.

What happens if I type a count above 100?

The count is corrected to a whole number from 1 to 100, and a note under the field says how many were generated. Blank or invalid entries become one UUID.

Are the UUIDs stored or sent anywhere?

No. They are generated by your browser and only exist on the page, so reloading or leaving it discards the list. Copy or download anything you need to keep.

UUID Generator

Generate cryptographically random UUIDs in the browser.

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About UUID Generator

Test fixtures, database seeds and idempotency keys all need identifiers that will not collide. Choose a count and press Generate: every value is a version 4 UUID, produced by the browser's crypto.randomUUID from its secure random source. Five appear as soon as the page opens, a batch can hold up to 100, and the whole list can be copied as one block with a UUID on each line.

Features

Version 4 UUIDs from the Web Crypto random source
Batches of 1 to 100 in one press
Copy each value on its own or the whole list at once
Corrects a count outside the allowed range and says so
Plain-text download with one UUID per line

Limitations

Only version 4 (random) UUIDs are produced: there are no time-based, name-based or version 7 options.
Values are always lowercase with hyphens; there is no uppercase, brace or hyphen-free variant.
Downloading uuids.txt needs a free account; copying the list does not.

How it works

Enter how many UUIDs you need in the How many UUIDs box.
Select Generate. A list is already there when the page opens, and each press replaces it with new values.
Copy a single value with its own Copy button, or select Copy all to take the whole list, one per line.
Use Download to save the list as uuids.txt, or Reset to clear it and set the count back to five.

Example input

550e8400-e29b-41d4-a716-446655440000

Frequently asked questions

: From the browser's crypto.randomUUID, which draws on a cryptographically secure generator. If a browser lacks that function, the page fills sixteen random bytes with crypto.getRandomValues and sets the version and variant bits itself.
: In theory yes, in practice almost never: a version 4 UUID has 122 random bits. This page does not check values against your database, so keep a unique constraint on the column as a safety net.
: The count is corrected to a whole number from 1 to 100, and a note under the field says how many were generated. Blank or invalid entries become one UUID.
: No. They are generated by your browser and only exist on the page, so reloading or leaving it discards the list. Copy or download anything you need to keep.