UUID Generator
Generate random UUID v4 and time-ordered UUID v7 identifiers, one or thousands at a time. Cryptographically random, generated in your browser.
Result
The result appears here as you type.
What this tool is for
Generate UUIDs in bulk for seeding a database, writing tests or naming resources. Version 4 is fully random. Version 7, standardised in 2024, puts a timestamp in the high bits so identifiers sort chronologically, which makes them far kinder to a database index than v4.
How to use it
- Choose the version: v4 for pure randomness, v7 when the values become primary keys.
- Set how many you need.
- Copy the list, with or without hyphens, in the letter case you prefer.
Frequently asked questions
v4 or v7 for a database key?
v7. Random v4 keys scatter inserts across the whole index, fragmenting it and hurting write performance. v7 values increase over time, so inserts land at the end of the index like an auto-increment column, while staying globally unique.
Can two UUIDs collide?
A v4 UUID has 122 random bits. You would need to generate billions per second for a century before a collision became likely. In practice the risk is a bug in a weak random source, not the mathematics, which is why this uses the browser crypto API.