Online UUID Generator v4
Generate UUID v4 (RFC 4122) instantly in your browser. Bulk generate, choose standard/no-hyphen/braces/URN formats, toggle uppercase, and copy results.
How to use
Use the generator to create RFC 4122 UUID v4 strings in the format your app expects.
- Set how many UUIDs you want (1–500).
- Choose an output format (standard, no hyphens, braces, or URN).
- Optionally enable uppercase output.
- Click Generate, then Copy to copy all results.
FAQ
What is a UUID v4?
A UUID v4 is a 128-bit identifier generated from random data, formatted per RFC 4122 (e.g., xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx).
Is this UUID generator truly random?
When “Use crypto” is enabled, it uses crypto.getRandomValues for strong randomness; otherwise it falls back to Math.random, which is weaker.
Does this tool send anything to a server?
No. Generation happens locally in your browser with no network requests.
What formats can I output?
Standard (hyphenated), compact (no hyphens), braces ({uuid}), and URN (urn:uuid:uuid).
Can UUIDs collide?
In practice, collisions for properly generated v4 UUIDs are extremely unlikely, but no scheme can guarantee “never” across all time and systems.
Are UUID v4 values safe for database primary keys?
Often yes, but consider index/fragmentation tradeoffs; some databases perform better with time-ordered IDs (e.g., UUIDv7/ULID).
How do I validate a UUID v4?
Use a regex that checks version 4 and the RFC 4122 variant, such as: ^[0-9a-f]{8}-[0-9a-f]{4}-4[0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$.
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