UUID Generator
Create unique IDs with no risk of collision. Generate random UUID v4, time-sorted UUID v7 and ULID, up to 1000 at a time, then copy or save them.
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How to use
When it helps
A UUID is a 128-bit value designed so anyone can create IDs that never clash, without asking a central server. Use them for database primary keys, file names, order numbers or fake test data. Random v4 UUIDs have 2 to the 122nd power possible values, so collisions practically never happen.
UUID v7 and ULID store the creation time in milliseconds at the front, so they sort in the order they were made. That gives better database index performance than v4, which is why they have become popular. Paste a v7 or ULID into the inspect box to see when it was created.
All values come from the browser's cryptographic random generator (crypto.getRandomValues), so they are hard to guess. Even so, do not use IDs as a replacement for passwords or auth tokens.
FAQ
Should I use v4 or v7?
If order does not matter, v4 is the safe default. If time ordering and index performance matter, as with database primary keys, v7 is a better fit.
How is ULID different from UUID?
A ULID is also 128 bits and sorts by time. It is written as 26 uppercase letters and digits (Crockford Base32), so it is shorter and easier to read than a UUID.
Can they really never collide?
v4 has 122 random bits, so even billions of IDs have a near-zero chance of a clash. v7 and ULID also differ in their random part within the same millisecond.
Are GUID and UUID the same thing?
Yes. GUID is Microsoft's name for it. Turn on the braces option if you need the {...} format.
How many can I make at once?
Up to 1000 at a time. If you need more, generate several batches and combine them.