UUID Generator
Generate cryptographically random v4 UUIDs in bulk.
Generated UUIDs
Press Generate to create v4 UUIDs.
Example:3f2504e0-4f89-41d3-9a0c-0305e82c3301 — 122 random bits from your browser's cryptographic random number generator.
About UUID Generator
A UUID is a 128-bit identifier that can be generated independently on many machines with a negligible chance of collision, which makes it ideal for database primary keys, correlation IDs and idempotency keys.
Version 4 UUIDs are made almost entirely of random bits, with six bits reserved to mark the version and variant. This generator uses the Web Crypto API, so the values are suitable for real use rather than just for mock data.
How UUID Generator works in your browser
UUIDs are generated with crypto.randomUUID where available, falling back to crypto.getRandomValues — both are the browser’s cryptographically secure random number generator. The version and variant bits are set according to RFC 4122 version 4, leaving 122 random bits.
Output can be switched between lowercase, uppercase, braced GUID style or a plain 32-character hex string, and generated in bulk.
When to use it
- Creating primary keys or idempotency keys for test data.
- Generating correlation IDs for tracing requests across services.
- Producing Microsoft-style braced GUIDs for configuration files.
Frequently asked questions
Are these UUIDs random enough for production?
Yes. They come from the browser cryptographically secure random number generator and follow RFC 4122 version 4.
What is the chance of a collision?
A v4 UUID carries 122 random bits. You would need to generate billions of them before a collision becomes remotely likely.
Can I get uppercase or braced output?
Yes, use the format options to switch between lowercase, uppercase, braced Microsoft-style GUIDs, or a plain 32-character hex string.