Which version should I use?

v4 is the safe default. v7 is better for database primary keys because it's time-ordered and index-friendly. v1 is legacy.

Are v4 UUIDs cryptographically random?

Yes — they use the browser's crypto.getRandomValues.

Which UUID version should I use?

Version 4 is the safe default: purely random, no embedded metadata. Choose a time-ordered version such as v7 when identifiers are also primary keys and you want index locality in the database.

Can two generated UUIDs collide?

In practice, no. A v4 UUID carries 122 random bits; you would need to generate billions per second for decades before a collision became likely. That is why coordination-free identifiers work at all.

Are these random values cryptographically strong?

Yes. Generation uses the Web Crypto API's crypto.getRandomValues, not Math.random, so the output is suitable wherever unpredictable identifiers are required.

UUID Generator — v1, v4, v7

Generate identifiers in the three most useful UUID versions: v1 (timestamp), v4 (random), and v7 (time-ordered, sortable). Bulk generate up to 1000 at a time.

Last updated: 2026-07-21 · Runs 100% in your browser

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Click Generate to create UUIDs.

// What is the UUID Generator?

The UUID Generator produces RFC 4122 universally unique identifiers in bulk, using your browser's cryptographic random number generator rather than a predictable pseudo-random source. Generate one identifier or hundreds at a time, then copy the batch straight into a seed script, a test fixture or a migration. UUIDs let independent systems mint identifiers without coordinating with a central sequence, which is what makes them the default choice for distributed systems, offline-capable clients and event streams. Because generation happens locally, the identifiers exist only in your tab until you copy them — no server ever sees which values you produced, and there is no rate limit on how many you generate.