UUIDs Explained: What They Are and How to Use Them
Everything you need to know about UUIDs — how they work, different versions, and when to use each type in your applications.
What is a UUID?
A UUID (Universally Unique Identifier) is a 128-bit identifier standardized by RFC 4122. UUIDs are designed to be unique across space and time, making them ideal for distributed systems where IDs must not conflict.
UUID v4 — Random UUIDs
UUID v4 is the most commonly used version. It generates IDs using random numbers, with 122 bits of randomness. The probability of collision is extremely low, making it suitable for most applications.
UUID v7 — Time-Ordered UUIDs
UUID v7 is a newer version that combines a timestamp with random bits. This makes UUIDs sortable by creation time, improving database index performance compared to v4.
When to Use UUIDs
UUIDs are ideal for distributed systems, database primary keys, API identifiers, and any scenario where you need globally unique identifiers without a central authority.
Using WebUtil's UUID Generator
Our free UUID Generator creates UUID v4 identifiers instantly. You can generate single or multiple UUIDs at once, with bulk generation supporting up to 100 IDs at a time.
Use our free online tool to get started instantly.