UUID Generator Online Free — Generate UUID v4 Instantly
Generate cryptographically random UUID v4 identifiers online. Free, private, bulk copy — runs in your browser, no upload.
UUID v4 identifiers are 128-bit random values used as database primary keys, session IDs, correlation IDs, and test fixtures. RFC 4122 specifies the format: 8-4-4-4-12 hexadecimal digits with version and variant bits set.
How to generate a UUID online
- Open the UUID Generator — a new v4 value appears instantly
- Click Generate again for another random UUID
- Generate multiple UUIDs at once for seed data or load tests
- Copy with one click — nothing is sent to a server
UUID versions at a glance
- v4 — random (most common for general-purpose IDs)
- v1 — time-based (predictable — avoid for security tokens)
- v5 — deterministic hash of namespace + name
- v7 — timestamp-ordered (sortable, newer standard)
When to use UUID v4
- Database primary keys in distributed systems
- Request correlation IDs in microservices logs
- Temporary filenames and upload keys
- Mock data and API testing