What is UUID?

UUID stands for Universally Unique Identifier. It’s a 128-bit number used to uniquely identify objects, sessions, or resources across distributed systems without central coordination.

Example UUID: 550e8400-e29b-41d4-a716-446655440000

✅ Key Properties of UUID

• Universally unique — designed to be unique across space and time.
• 128-bit size, offering ~3.4 × 10³⁸ possible values.
• Used in distributed systems without central coordination.
• Different versions exist like UUIDv1 (timestamp & MAC address based) and UUIDv4 (random).

✅ Why Is It Hard to Duplicate?

• Huge number of possible values: Duplicates are statistically improbable.
• Unique factors: Some versions use timestamps, MAC addresses, or randomness.
• No coordination needed: Systems can generate UUIDs independently.
• Negligible collision probability: Practically treated as impossible.

Note: While duplication is theoretically possible, it’s practically negligible unless a system is flawed or manipulated.

✅ Where Are UUIDs Used?

• Database primary keys
• Distributed systems for tracking objects or sessions
• File systems for unique file identifiers
• APIs for identifying requests or resources
• Software licensing and tokens

📘 Summary

• A UUID is a 128-bit globally unique identifier used to distinguish objects across systems.
• Its uniqueness comes from its size and combination of random or time-based factors.
• Duplication is almost impossible, making it perfect for distributed systems.