UUID generator

UUID generator features

• 01

  UUID v4 and UUID v7

  v4 is the classic fully-random UUID used everywhere; v7 embeds a millisecond timestamp at the start, so IDs sort chronologically — ideal for database primary keys that need good index locality.

• 02

  Bulk generation

  Need 100 UUIDs for a test fixture? Drag the slider. Toggle lower/upper casing, dashes, and curly-brace wrapping to match your environment, then copy the whole block or download as a .txt file.

• 03

  Cryptographically random

  Every UUID is generated with crypto.randomUUID (for v4) or crypto.getRandomValues (for v7) — the same secure random source used by HTTPS. No weak Math.random() fallback.

UUID generator FAQ

What is a UUID?

A UUID (Universally Unique Identifier), also called GUID, is a 128-bit identifier designed to be unique across space and time without any central authority. UUIDs are the standard way to assign IDs to records, objects, and events in distributed systems.

Should I use UUID v4 or v7?

Use v4 when you want a fully-random ID with no embedded information. Use v7 as a database primary key — the leading timestamp makes inserts append-heavy instead of random, which dramatically improves B-tree index performance.

How unique are UUIDs really?

A random 128-bit UUID has 2^122 possible values. You would need to generate roughly 2.7 quintillion UUIDs to have a 1-in-a-billion chance of a collision. For every practical purpose, collisions are impossible.

Can I use this for security tokens?

UUID v4 uses the Web Crypto API, so it's cryptographically random and suitable for session IDs or short-lived tokens. For long-lived secrets, prefer a dedicated token format with authentication tags. UUID v7 reveals the creation time, so avoid it for anything security-sensitive.

Are the UUIDs sent anywhere?

No. Every UUID is generated locally using the browser's crypto API. Nothing is uploaded, logged, or stored.