Free tool
UUID Generator
Generate UUID v4 and v7, ULIDs and Nano IDs, one or a thousand at a time.
Generate identifiers in the format you need. Every value here comes from the browser crypto API, so they are cryptographically random rather than the output of Math.random, and none of them are sent anywhere.
Which format to pick depends on what the ID has to do. UUID v4 is pure randomness and the safe default. UUID v7 puts a millisecond timestamp in the high bits, so values sort chronologically, which keeps database indexes from fragmenting the way random keys do. ULID does the same in a shorter, case-insensitive, URL-friendly encoding. Nano ID is the most compact of the four at 21 characters and is best where the ID appears in a URL.
How to use it
- Pick the format you want and how many to generate.
- Adjust the case or hyphens if the target system is fussy about them.
- Press Generate for a fresh batch.
- Copy the whole list, or a single line by hand.
Frequently asked questions
Are these random enough to use in production?
Yes. They use crypto.getRandomValues, the same cryptographically secure source your server would use, and generation happens locally so no one else ever sees the values. As always, do not use an identifier as a security token unless it is meant to be unguessable and is long enough.
Should I use UUID v4 or v7 as a database key?
v7 in most cases. Because the leading bits are a timestamp, new rows land at the end of the index instead of scattering through it, which avoids the page splits and cache misses that make random v4 keys slow at scale. Use v4 when you specifically do not want creation time to be inferable from the ID.
What is the chance of a collision?
Negligible for any realistic volume. A v4 UUID has 122 random bits, so you would need to generate billions per second for a lifetime before a collision became likely. Nano ID at 21 characters is comparable in practice.
Why does ULID look different from a UUID?
It encodes the same kind of value in Crockford base32 rather than hexadecimal, giving 26 characters with no hyphens, no case sensitivity and no vowels that could form accidental words. It is friendlier in URLs and easier to read aloud.
The desktop version
UUID Generator in Toolbelt
This page does the job in a browser tab. Toolbelt is the same tool as a native Mac app, plus the things a web page cannot do.
Tools
{
"name": "Holizmi",
"tools": [
"json",
"jwt",
"base64"
],
"live": true
}{
"sub": "12345",
"name": "Henry",
"exp": 1767225600
}019bd4e2-7a10-7c3e-9f21-4a6b8d3e5c07
019bd4e2-7a11-7b8a-8e44-1c2f9a7d6b13
019bd4e2-7a12-7d5f-b0c9-7e3a1f8c2d95 1 1 one
2 2 two
3 + inserted
3 4 three- A global shortcut that puts a fresh ID straight on your clipboard
- Generate directly into your editor without switching windows
- Remembers the format and count you actually use
- Works with no connection at all