How Client-Side Cryptographic UUID Generation Works
Secure UUID / GUID Generator runs entirely in your browser with JavaScript. There is no sign-up, and whatever you type or open here is processed on your device instead of being sent to a server.
Cryptographically Secure UUID Generation in Your Browser
Generate version-4 Universally Unique Identifiers (UUIDs) and Microsoft GUIDs with your browser's Web Crypto API (crypto.randomUUID, or crypto.getRandomValues in older browsers). Unlike Math.random, a cryptographically secure generator makes the identifiers unpredictable and a collision between two of them astronomically unlikely.
Bulk Generation with Custom Formatting
Generate single identifiers or batches of hundreds of UUIDs in seconds. Choose lowercase or UPPERCASE and turn hyphens on or off; each UUID goes on its own line, ready to paste into your database schema or code fixtures. Only random version 4 UUIDs are generated; time-ordered versions such as v1 or v7 are not available.
Zero Server Transmission for Database Security
Every generated identifier is minted entirely inside your browser memory. They are never sent to or logged on any external server, eliminating risks of ID harvesting for sensitive database keys.
Anatomy of a Version 4 UUID
A UUID is 128 bits written as 32 hexadecimal digits in five groups of 8-4-4-4-12, which makes 36 characters with the hyphens, for example 3f2b8c1e-9a4d-4c7b-b5e2-1d6f0a9c8e47. In a version 4 UUID the first digit of the third group is always 4 (the version) and the first digit of the fourth group is 8, 9, a or b (the variant); the other 122 bits are random. With that many random bits, the chance of this online UUID generator producing the same value twice is too small to matter in practice, which is why UUIDs work as database keys and file names without a central counter. Turning hyphens off gives the same 32 digits for systems that expect them without separators.
Generating UUIDs in Code
This generator uses your browser's crypto.randomUUID(), the same call you can use in your own JavaScript. Other languages and databases have their own; most give version 4 UUIDs, but MySQL's UUID() is time-based (version 1). GUIDs are often written in upper case and sometimes in braces: tick Uppercase here, and add the braces yourself if your system needs them.
| Language or database | Code | What you get |
|---|---|---|
| JavaScript | crypto.randomUUID() | Version 4, in lower case (browsers and Node.js) |
| Python | uuid.uuid4() | Version 4 (import uuid first) |
| PostgreSQL 13 and later | gen_random_uuid() | Version 4 |
| MySQL | UUID() | Version 1, based on time and the machine, not random |
| SQL Server | NEWID() | A random GUID (version 4) |
| C# / .NET | Guid.NewGuid() | Version 4; .ToString("B") adds the braces |
Why processing in your browser matters
Many online tools upload your files or text to a server to process them. This one does the work on your computer or phone, so your data is not sent to us or stored anywhere else. That lowers the risk when you work with confidential material, although you should still follow your organisation's own rules. Read how this works in our Privacy Policy.
- No uploads: files are opened and saved on your device, so there is no upload or download wait.
- No account: nothing to sign up for or install.
- Free to use: no subscriptions or paywalls.