Lesson 4
Formats and Validation
Canonical, compact, braced, and URN forms plus version and variant checks.
The canonical UUID format is lowercase hex in an 8-4-4-4-12 layout:
550e8400-e29b-41d4-a716-446655440000
You may also see:
- Compact UUIDs without hyphens
- Uppercase UUIDs
- Braced UUIDs like
{550e8400-e29b-41d4-a716-446655440000} - URNs like
urn:uuid:550e8400-e29b-41d4-a716-446655440000
Validation should check more than length. A useful validator normalizes the format, confirms hexadecimal groups, reads the version digit, and checks the variant bits.