UUID Generator
Generate UUID v4 and GUID-style identifiers in bulk, with uppercase, no-dash, and brace formatting options.
About UUID v4
- 128 bits, 32 hex characters, 8-4-4-4-12 format
- Version 4 is generated through the Web Crypto API: crypto.randomUUID() or crypto.getRandomValues()
- Collisions are extremely unlikely, but not mathematically impossible
- UUIDs are identifiers and should not be used as access secrets
Generate UUID v4 values
Generate random UUID v4 identifiers for databases, API resources, test fixtures, trace IDs, correlation IDs, and local development tasks.
- Create one UUID or a bulk list up to 100 values.
- Use canonical lowercase format, uppercase GUID style, no dashes, or braces.
- Copy one identifier or the whole generated list.
UUID v4 format
UUID is the identifier, 128 bits is its total size, and 32 hex is the compact hexadecimal representation.
r is the random space after version and variant bits are fixed.
RFC 9562 is the current UUID specification. UUID v4 uses random bits plus fixed version and variant fields, and many GUID tools expose the same identifier family with different display formatting.
Collision and security notes
UUID v4 collisions are extremely unlikely with a good random source, but not mathematically impossible. Databases should still enforce uniqueness when IDs must be unique.
Frequently Asked Questions
Sources and References
- RFC 9562: Universally Unique IDentifiers (UUIDs)IETF
- Crypto: randomUUID() methodMDN
- UUID Generator OnlineUUID Builder
Calculations are based on the listed reference sources. Links open in a new tab.