UUID Generator

How to generate UUIDs

1. Choose the type of ID: UUID v4, UUID v7, ULID or NanoID.
2. Set how many you need (up to 1,000) and the format options.
3. Copy the list, or click Generate for a fresh batch.

UUID versions at a glance

• v1: timestamp plus the machine's MAC address. Leaks hardware info; avoid for new systems.
• v4: 122 random bits. The default choice when order does not matter.
• v6: like v1 but reordered so it sorts by time.
• v7: Unix milliseconds plus random bits (RFC 9562). Sortable and great for database keys.

Frequently asked questions

Which UUID version should I use?

Use UUID v4 when you just need a random unique ID. Use UUID v7 for database primary keys: it starts with a timestamp, so new IDs sort after old ones and keep B-tree indexes compact.

Can two generated UUIDs collide?

In practice, no. A v4 UUID has 122 random bits. You would need to generate about a billion UUIDs per second for 85 years to reach a 50% chance of a single collision.

What are ULID and NanoID?

ULID is a 26-character, time-sortable ID in Crockford Base32, similar in purpose to UUID v7. NanoID is a short random ID (21 characters by default) using a URL-safe alphabet, handy for public-facing IDs.

Are these IDs secure?

They are generated with the browser's cryptographically secure random number generator (crypto.getRandomValues). Still, do not use IDs as secrets or access tokens.