UUID Validator

UUID (Universally Unique Identifier) is a 128-bit number used to uniquely identify information in computer systems. Displayed as 32 hexadecimal digits in the format xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx, UUIDs are virtually guaranteed to be unique globally without requiring a central authority.

UUID v1 uses timestamp and MAC address (time-based). UUID v2 is DCE Security (rarely used). UUID v3 uses MD5 hashing of a namespace and name. UUID v4 is randomly generated (most common). UUID v5 uses SHA-1 hashing. Each version has specific use cases based on uniqueness requirements and generation method.

A valid UUID must be 36 characters long (32 hex digits and 4 hyphens) in the format 8-4-4-4-12. The version number appears in the 13th position, and variant bits determine the UUID standard. Our validator checks format, identifies version, verifies variant, and extracts timestamps from v1 UUIDs.

UUID (Universally Unique Identifier) and GUID (Globally Unique Identifier) are essentially the same concept. GUID is Microsoft's term for UUID. They both represent 128-bit unique identifiers, though GUIDs may sometimes use different formatting conventions in Microsoft systems.

UUID v1 contains extractable timestamp and node information (MAC address). Our validator displays the creation timestamp for v1 UUIDs. UUID v3/v5 contain hash values but no extractable metadata. UUID v4 is purely random with no embedded information beyond version and variant.

UUID v4 (random) is recommended for most applications due to simplicity and no privacy concerns. Use v1 if you need time ordering. Use v3/v5 if you need deterministic UUIDs from names (v5 preferred over v3 due to stronger SHA-1 hashing vs MD5).

UUIDs are probabilistically unique, not absolutely unique. UUID v4 has ~5.3 × 10^36 possible values, making collision probability negligible (1 in 103 trillion if generating 1 billion UUIDs per second for 85 years). For practical purposes, they're considered unique.

The variant indicates which UUID standard is used. RFC 4122 is the most common variant (the Internet standard). Other variants include Reserved (NCS backward compatibility), Microsoft (GUID), and Reserved (future use). Our validator identifies the variant from the UUID's variant bits.

Yes, UUIDs work as primary keys and offer advantages: globally unique (useful for distributed systems), no central ID generator needed, and difficult to guess. Downsides include larger storage (16 bytes vs 4-8 for integers) and potential index performance impact. UUID v1 performs better for sequential inserts.

Most programming languages have built-in UUID generation: JavaScript (crypto.randomUUID()), Python (uuid.uuid4()), Java (UUID.randomUUID()), PHP (uniqid() or ramsey/uuid package), and Node.js (crypto module). Online generators are also available for testing purposes.

The NIL UUID (00000000-0000-0000-0000-000000000000) is a special UUID with all bits set to zero. It's used to represent null or undefined values in contexts requiring a UUID, similar to how null works for other data types.

No, UUIDs are not case-sensitive. Both uppercase and lowercase hexadecimal characters are valid (550e8400-e29b-41d4-a716-446655440000 equals 550E8400-E29B-41D4-A716-446655440000). However, lowercase is the standard convention for display.

Only UUID v1 reveals information - it contains timestamp and MAC address (though MAC may be randomized for privacy). UUID v3/v5 are one-way hashes. UUID v4 is random and reveals nothing. Our validator extracts available metadata like version, variant, and v1 timestamps.