How to Generate a UUID (v4)

UUIDs come in several versions. Version 1 is based on your timestamp and network MAC address; version 4 is generated from random (or pseudo-random) numbers. Tooldrop produces v4 UUIDs, which look like this: 3f2504e0-4f89-41d3-9a0c-0305e82c3301. The digit in the third group is always 4 (marking the version), and the first digit of the fourth group is 8, 9, a, or b (the variant) — the rest is randomness.

That randomness is what makes v4 so popular: there's no central registry and no coordination needed. Two people on opposite sides of the world can both generate a v4 UUID and the odds of a clash are astronomically small. Because v4 carries no timestamp or hardware identifier, it also doesn't leak information about where or when it was created — a nice privacy bonus over v1.

Tooldrop's UUID generator calls crypto.randomUUID() from the browser's Web Crypto API. That's the same secure randomness source browsers use for sensitive cryptographic work, so these aren't just "good enough" random numbers — they're cryptographically strong. That matters if your UUIDs double as hard-to-guess tokens or session IDs.

Just as important: the generation happens locally, in the tab you have open. No UUID is sent to a server, logged, or stored. If you generate a batch of IDs for production keys or test fixtures, they exist only on your machine until you copy them somewhere. That on-device approach is how most Tooldrop tools work, which is why you can use them freely without an account.

For seeding a database, building a fixtures file, or stress-testing an API, you'll often want a list of UUIDs rather than one. Set the "How many" field to the count you need (up to 100 in the interface), click Generate, and you'll get a clean, line-separated list in the Result panel.

Click Copy all and paste the whole block straight into your code editor, a CSV column, a SQL insert, or a spreadsheet. Each value is unique, so there's no need to de-duplicate. Want a completely different set? Click Generate again — every run is independent and fully random.