Generate Secure v4 UUIDs in Bulk
Cryptographically secure, multiple formats, inline validator. Everything runs in your browser.
3fa85f64-5717-4562-b3fc-2c963f66afa6Validate a UUID
UUIDs are generated using crypto.randomUUID() — cryptographically secure, entirely in your browser.
What are UUIDs used for?
- Database primary keys — decentralised ID generation without a sequence.
- API resources — stable identifiers that don't expose enumeration.
- Session tokens — unpredictable identifiers for user sessions.
- File names — avoid collisions when uploading user content.
- Distributed systems — generate IDs on any node without coordination.
Frequently asked questions
A UUID (Universally Unique Identifier) is a 128-bit label used to uniquely identify objects in computer systems. It is represented as a 32-character hexadecimal string split into 5 groups: xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx. Version 4 UUIDs are randomly generated.
UUID v4 uses a cryptographically secure random number generator (crypto.randomUUID in modern browsers). The probability of generating two identical UUIDs is astronomically small — approximately 1 in 5.3 × 10^36 — making collisions practically impossible.
UUID and GUID (Globally Unique Identifier) refer to the same concept. UUID is the standard term defined by RFC 4122; GUID is Microsoft's term for the same thing.
Use v4 when you need a completely random ID with no embedded meaning — database primary keys, session tokens, file names. Use v1 (time-based) if you need sortable IDs. Use v5 (name-based SHA-1) if you need deterministic IDs from a namespace and name.
Standard: 3fa85f64-5717-4562-b3fc-2c963f66afa6. Uppercase: same with capital letters. No hyphens: 32-character hex without dashes. Braces: {3fa85f64-5717-4562-b3fc-2c963f66afa6} — used in some Windows and .NET APIs.
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