UUID Generator

About UUID Generation

A UUID (Universally Unique Identifier), also known as a GUID (Globally Unique Identifier), is a 128-bit identifier that is practically guaranteed to be unique across all systems and time. Our generator creates UUID version 4, which uses random or pseudo-random numbers and follows the RFC 4122 standard.

UUID v4 Format

A UUID v4 looks like: 550e8400-e29b-41d4-a716-446655440000. It consists of 32 hexadecimal characters divided into 5 groups by hyphens (8-4-4-4-12). The 13th character is always 4 (indicating version 4), and the 17th character is always 8, 9, a, or b.

Common Use Cases

• Database primary keys — Distribute records across systems without collision
• Session tokens — Uniquely identify user sessions
• File naming — Generate unique filenames for uploaded files
• Microservices — Track requests across distributed systems
• Testing & seeding — Create unique IDs for test data

Are UUIDs Truly Unique?

UUID v4 uses 122 bits of randomness, yielding 2^122 (≈ 5.3 × 10^36) possible values. The probability of generating a duplicate UUID in a system generating 1 billion UUIDs per second for the next 100 years is negligibly small — effectively impossible for any real-world application. Our generator uses crypto.getRandomValues() for maximum randomness quality.