UUID Generator
The UUID generator produces RFC 4122 version 4 (random) and version 7 (time-ordered) identifiers using the browser cryptographic random number generator. Generate up to 1,000 at a time, with or without hyphens, in upper or lower case.
UUIDs
Set your options and press the generate button.
Results update automatically and are calculated on your device. Nothing you type is sent to a server.
Runs in your browser. Processing happens entirely in your browser. Nothing you enter is sent to Delimiter.live.
How to use the UUID Generator
- Choose the version — v4 for general use, v7 when you want identifiers that sort by creation time.
- Set how many you need, up to 1,000.
- Adjust the formatting options if your system expects uppercase or braces.
- Press Generate, then copy or download the list.
Example
Input
v4, quantity 2
Output
9f1c2b7e-4a3d-4c88-9f0e-1b2c3d4e5f60 2a7d9e11-8c4b-4f2a-b6d3-0e9f8a7b6c5d
Common use cases
- Creating primary keys for records inserted outside a database sequence.
- Generating correlation IDs for tracing a request across services.
- Producing unique file names or idempotency keys.
- Seeding test fixtures with realistic identifiers.
Limitations and things to watch for
- Version 4 UUIDs are random, so they do not sort meaningfully and can fragment a clustered database index. Version 7 embeds a millisecond timestamp in the high bits, which keeps inserts sequential — prefer it for primary keys in new systems.
- The nil UUID is all zeroes and is a valid placeholder value, not a generated identifier.
- Randomness comes from crypto.getRandomValues(), which is the browser cryptographically secure generator.
Frequently asked questions
Are these UUIDs cryptographically random?
Yes. They are generated with crypto.getRandomValues(), the browser cryptographically secure random source. Version 4 UUIDs carry 122 bits of randomness, which makes an accidental collision effectively impossible.
When should I use v7 instead of v4?
Use v7 for database primary keys. Its leading millisecond timestamp means new rows insert at the end of an index rather than scattering through it, which avoids the write amplification random v4 keys cause.
Are the generated values sent to a server?
No. Generation happens in your browser and nothing is transmitted or stored, so the values are yours alone.
What is the difference between a UUID and a GUID?
None in practice. GUID is Microsoft terminology for the same 128-bit identifier format, which is why GUIDs are often written in uppercase inside braces — both options are available here.