Generate unique identifiers (UUIDs)
A UUID (Universally Unique Identifier) is a 128-bit value used as a unique identifier without coordination between systems. v4 UUIDs are random (best for opaque IDs); v1 UUIDs are time-based (sortable by creation). This generator produces spec-compliant RFC 4122 v1 and v4 UUIDs using cryptographically secure randomness — many other online tools use Math.random, which is predictable and unsafe for security-sensitive use.
v1 encodes a timestamp and machine identifier — it's sortable by creation time but leaks info. v4 is fully random — collision-safe and opaque, the modern default.
v7 (time-ordered random) is excellent for database primary keys because it indexes efficiently. It's a 2024 RFC addition, increasingly supported — we're adding it in a follow-up release.
We use crypto.getRandomValues (or crypto.randomUUID when available), both backed by OS-level CSPRNGs. Collision probability for 122 random bits is astronomically low.
We cap the UI at 100 per batch to keep the page responsive. For higher volumes, call crypto.randomUUID in your own script.
For v4, yes — the collision probability is ~1 in 2^122, practically zero. For v1, uniqueness depends on the machine ID + clock sequence; two processes on the same machine could theoretically collide.
