UUID Generator

UUID v4 Generator — Random Unique Identifiers

Universally Unique Identifiers (UUIDs) are 128-bit numbers used to uniquely identify information in computer systems. Version 4 UUIDs are randomly generated, providing approximately 5.3 x 10^36 possible values — enough to assign a unique ID to every grain of sand on Earth with room to spare. This generator uses the browser's built-in crypto.randomUUID() method (or a conformant fallback) to produce RFC 4122-compliant UUIDs. You can generate single UUIDs with customizable formatting — uppercase or lowercase, with or without hyphens, wrapped in braces for C#/.NET compatibility — or bulk generate up to 1,000 UUIDs at once for seeding databases, creating API keys, or generating test data.

Common UUID Use Cases

UUIDs are used extensively in distributed systems where unique identifiers must be generated without a central coordinator. Common applications include database primary keys (especially in sharded or replicated databases), session identifiers, transaction IDs, API keys, correlation IDs for logging and tracing, and filenames in distributed file systems. Unlike auto-incrementing integers, UUIDs can be generated by any node in a system without coordination or collisions. This tool generates all UUIDs locally using cryptographically secure randomness — your identifiers are created on your device and never transmitted anywhere.