🆔 UUID Generator

What is a UUID?

A UUID (Universally Unique Identifier) is a 128-bit value used to uniquely identify information across systems without central coordination. UUIDs are standardised in RFC 4122 and are widely used as primary keys in databases, session tokens, file names, and anywhere a unique identifier is needed without a central authority issuing them.

UUID v4 — the random version

Version 4 UUIDs are generated using random (or pseudo-random) numbers. With 122 bits of randomness, the probability of a collision is astronomically low — roughly 1 in 5.3 × 10³⁶. UUID v4 is the most commonly used version for general-purpose identifiers because it requires no network calls or server coordination.

Format: with and without dashes

A standard UUID looks like 550e8400-e29b-41d4-a716-446655440000 — 32 hex characters split into 5 groups by hyphens. Some systems prefer the compact form without dashes: 550e8400e29b41d4a716446655440000. Both represent the same value; the choice is a matter of convention in your codebase or API.

Common use cases

UUIDs are used as database primary keys (especially in distributed systems where auto-increment is problematic), unique file names to avoid collisions, idempotency keys in payment APIs, request tracing and correlation IDs, and as session or API tokens when combined with additional signing.

Is it safe to generate UUIDs in the browser?

Yes. This tool uses the crypto.randomUUID() API (or falls back to crypto.getRandomValues()) which is backed by the operating system's cryptographically secure random number generator — the same source used by server-side UUID libraries. No data is sent to any server.