UUID Generator

UUID Generator — What Is a UUID and Why Use It?

A UUID (Universally Unique Identifier) is a 128-bit label used to uniquely identify objects in computer systems. UUIDs are standardized by RFC 4122 and are designed to be unique across space and time — two systems generating UUIDs independently will almost certainly generate different ones.

UUID Format

A UUID looks like this: 550e8400-e29b-41d4-a716-446655440000. It is displayed as 32 hexadecimal digits in 5 groups separated by hyphens: 8-4-4-4-12 characters. Total: 32 hex digits = 128 bits.

UUID Versions

• Version 1: Based on time and MAC address. Predictable — contains hardware info.
• Version 3: Based on MD5 hash of a namespace and name. Deterministic.
• Version 4: Completely random (122 random bits). Most commonly used. This is what our generator creates.
• Version 5: Based on SHA-1 hash. More secure than v3.

Why Use UUIDs Instead of Sequential IDs?

• Security: Sequential IDs (1, 2, 3...) are predictable. Users can guess other record IDs. UUIDs are unpredictable.
• Distributed Systems: Multiple servers can generate unique IDs without coordinating with a central database.
• Merging Databases: When merging two databases, sequential IDs will clash. UUIDs won't.
• Microservices: Each service can generate IDs independently.

UUID Collision Probability

UUID v4 has 2^122 possible values (about 5.3×10^36). To have a 50% chance of a single collision, you would need to generate over 10^18 (one quintillion) UUIDs. In practice, UUID v4 is considered collision-proof.