Overview
Generate UUID v4 values for unique identifiers, trace IDs, idempotency keys, and database primary keys. Quick and local—no server involved.
Use cases
- Create an idempotency key for a payment or API request.
- Generate trace/request IDs to correlate logs across services.
- Seed test fixtures with realistic UUIDs.
Common pitfalls
- UUIDs can leak through logs and URLs—treat them as identifiers, not secrets.
- Some databases have performance considerations with random UUID primary keys; consider ULIDs/ordered UUIDs if needed.
FAQs
Is UUID v4 secure?
UUID v4 is random and usually excellent for uniqueness. Security depends on your use case—don’t use it as a secret token.
Can I generate multiple UUIDs at once?
Yes, generate in batch and copy.
Why do some UUIDs start with different characters?
UUID v4 has fixed version bits (the 13th hex digit is 4). The rest is random.
Will this ever collide?
In practice, collisions are extremely unlikely for v4 at typical scales.
Examples
Input
count=3
Output
xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx ...