UUID Generator
Generate v4 and v7 UUIDs using your browser crypto API.
Runs entirely in your browser.
Your data never leaves this device and is never sent to our servers.
UUIDs
A UUID is a 128-bit identifier you can generate anywhere without coordinating with a database. Version 4 is entirely random. Version 7 puts a millisecond timestamp in the leading bits, so identifiers sort chronologically — which matters a great deal if they are also a database primary key.
How to use it
- Choose v4 for pure randomness, or v7 if the values will be indexed.
- Set how many you need.
- Copy or download the list.
Not working as you expect? Report a problem with this tool.
Frequently asked questions
Should I use v4 or v7 as a primary key?
v7. Random v4 values scatter inserts across a B-tree index, fragmenting it and slowing writes. v7 values increase over time, so inserts stay at the end of the index like an auto-increment.
Are these safe to use as secrets?
v4 UUIDs are generated with the crypto API and have 122 random bits, so they are unguessable. They are still identifiers, not credentials — do not use one in place of a session token.
Can two UUIDs collide?
In practice, no. You would need to generate billions per second for many years before collision became plausible.