UUID Generator Developer
Generate cryptographically random version-4 UUIDs in bulk.
UUID Generator is a free online tool that generate cryptographically random version-4 UUIDs in bulk. It runs entirely in your web browser using WebCrypto, so files are processed on your own device and never uploaded to a server. There is no sign-up, no file size limit imposed by the site, no watermark and no paid tier.
- Price
- Free — no account, no quota, no watermark
- Category
- Developer
- Where it runs
- In your browser, on your device
- Files uploaded
- None
- Technology
- WebCrypto
- Settings
- 4
- Works offline
- Yes, after the first visit
About UUID Generator
UUID Generator is one of 43 developer tools on DuckyTools, and like all of them it runs entirely inside this page. Generate cryptographically random version-4 UUIDs in bulk.
How to use it
- Enter how many, case and wrap in braces.
- Adjust the remaining 1 setting if the defaults do not fit your case.
The 4 settings
| Setting | What it does | Default |
|---|---|---|
| How many | Range 1–1000. | 10 |
| Case | Choose from 2: lowercase, UPPERCASE. | lowercase |
| Wrap in braces | On or off. Off by default. | Off |
| Include hyphens | On or off. On by default. | On |
Under the hood
| Runs on | WebCrypto — supplies cryptographic randomness |
| Controls | How many, Case, Wrap in braces, Include hyphens |
Questions
Are these actually random?
Yes — they come from crypto.randomUUID(), which draws on your operating system's cryptographic random source. Version 4 UUIDs carry 122 random bits.
Could two of them ever collide?
In practice, no. You would need to generate about 2.7 × 10^18 of them for a 50% chance of a single collision. The usual advice is to worry about literally anything else.
Should I use a UUID as a database primary key?
It depends on your engine. Random v4 UUIDs scatter inserts across a B-tree index, which hurts write performance at scale — many teams prefer ULIDs or UUIDv7, which sort by time.