The UUID Generator creates cryptographically random Version 4 UUIDs in your browser using the Web Crypto API, as well as time-based v1 and v7 UUIDs for bulk export. It also supports deterministic v3 / v5 with DNS / URL / OID / X500 namespaces and a timestamp extraction inspector for v1 and v7. UUIDs are used as primary keys in databases, session identifiers, file names, and anywhere a globally unique identifier is needed. Bulk-generate thousands at once and export as a plain list.
Frequently Asked Questions
What is a UUID?
A UUID is a 128-bit number formatted as 32 hexadecimal digits in the pattern xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx. Version 4 UUIDs are randomly generated with no embedded time or machine information.
Can two generated UUIDs ever be the same?
The probability is approximately 1 in 5.3 times 10 to the 36th power. UUID v4 collisions are so rare they are treated as impossible for any practical application.
What is the difference between UUID v1 and v4?
UUID v1 is based on the current timestamp and machine MAC address. UUID v4 is entirely random, making it more privacy-friendly and the most widely used version today.
Are these UUIDs cryptographically secure?
Yes. This tool uses the browser Web Crypto API (crypto.randomUUID or getRandomValues) which provides cryptographically strong randomness.
What is a namespaced UUID (v3 / v5)?
v3 and v5 are deterministic UUIDs derived from hashing a namespace UUID concatenated with a name. v3 uses MD5 and v5 uses SHA-1. The same namespace plus name always yields the same UUID — useful for stable identifiers such as URLs, DNS names, or OIDs.
What are the DNS, URL, OID, and X500 namespaces?
RFC 4122 defines four well-known namespace UUIDs: DNS (6ba7b810-9dad-11d1-80b4-00c04fd430c8), URL (6ba7b811-9dad-11d1-80b4-00c04fd430c8), OID (6ba7b812-9dad-11d1-80b4-00c04fd430c8), and X500 (6ba7b814-9dad-11d1-80b4-00c04fd430c8). Use DNS when your name is a hostname, URL when it is a URL, OID for ASN.1 object identifiers, and X500 for X.500 distinguished names. You can also paste any custom namespace UUID.
Should I use v3 or v5 for namespaced UUIDs?
Prefer v5 (SHA-1) for any new project. v3 (MD5) exists only for compatibility with older systems — both encode the same information but SHA-1 is less susceptible to collisions for this purpose.
How does the timestamp extractor work?
v1 UUIDs embed a 60-bit timestamp measured in 100-nanosecond intervals since 1582-10-15, and v7 UUIDs embed a 48-bit Unix millisecond timestamp in the first six bytes. The Inspect tab parses either format and shows the ISO 8601 timestamp plus a relative description (for example, '5 minutes ago'). v3, v4, and v5 UUIDs do not contain a meaningful timestamp.