What is a UUID?
A UUID (Universally Unique Identifier) is a 128-bit number formatted as xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx. UUID v4 uses random values, giving about 2122 possible combinations — effectively guaranteeing uniqueness without coordination.
Common Uses
- Database primary keys (no auto-increment guessing)
- Client-generated IDs before server round-trips
- Tracking / transaction identifiers
- Idempotency keys for API requests
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