Question 1

What is the difference between UUID v4 and v7?

Accepted Answer

v4 is entirely random. v7 puts a timestamp in the leading bits, so IDs generated later sort after earlier ones - which keeps database indexes from fragmenting the way random keys do. Use v7 for anything that becomes a primary key.

Question 2

Are these random enough to be unguessable?

Accepted Answer

Yes. They come from the browser's cryptographic random number generator, not Math.random, so they are suitable for identifiers that must not be predictable - a share link or a password reset token.

Question 3

What is a Nano ID for?

Accepted Answer

A shorter, URL-safe identifier. It fits in a link or a filename far more comfortably than a 36-character UUID while still being long enough not to collide in practice.

Question 4

Is anything about these IDs recorded?

Accepted Answer

No. They are generated in your browser and this site never sees them, which is the only sane arrangement for a value you may be about to use as a secret.

Question 5

Can it produce thousands at once?

Accepted Answer

Yes. Set the count and generate, then Copy all takes the whole list.

Free UUID and random ID generator