UUID Generator
Generate v4 and v7 UUIDs in bulk.
Runs entirely in your browser. Nothing you enter or upload leaves your device.
What the UUID generator does
A UUID, or universally unique identifier, is a 128-bit ID written as 32 hexadecimal characters in five hyphenated groups, such as 3f2b8c1e-…. Because it can be created anywhere without checking a central list, it suits database keys, file names, API request IDs and test data. This tool creates version 4 and version 7 UUIDs, one or a thousand at a time.
Developers use it to seed a database, fill in fixtures for a test suite, give records stable IDs before they’re saved, or grab a quick unique value for a config file. It’s also useful for checking what a v7 ID looks like before adopting it in a project.
How to use the UUID generator
- Choose Version 4 for random IDs or Version 7 for time-ordered IDs.
- Set how many you need (up to 1,000) and press Generate.
- Change the format if needed: uppercase, without hyphens, or wrapped in braces. Copy or download the list.
Understanding the results
Each UUID is on its own line, ready to paste into a script or spreadsheet. The format options reshape the same list rather than making a new one, so you can switch to uppercase or remove hyphens without losing IDs you’ve already noted. The braces option gives the {…} style some Windows and .NET tools expect. You can tell the version by the first digit of the third group: it’s always 4 or 7.
In a v7 batch, the first twelve characters hold the creation time in milliseconds, so the list comes out already sorted and the IDs share a common start. That’s expected, not a fault. It helps databases insert rows in order, but it also means anyone can read roughly when the ID was made. If that matters, for example in public links, use version 4 instead.
Questions
v4 or v7?
Version 7 (RFC 9562) starts with a millisecond timestamp, so new IDs sort after older ones. That keeps database indexes compact. Version 4 is fully random and reveals nothing about when it was made.
Can two UUIDs collide?
In practice, no. A v4 UUID has 122 random bits. A v7 UUID here has 62 random bits after the timestamp, plus a 12-bit counter that keeps IDs from the same millisecond in order.
Where does the randomness come from?
Your browser’s cryptographically secure random generator. Nothing is fetched from a server.
Should I store UUIDs with or without hyphens?
Either works, as long as you’re consistent. Many databases have a native UUID type that stores the 16 bytes compactly whatever the text format.