ToolWren › UUID

UUID & ULID Generator

Generate one or many random UUID v4 or ULID identifiers, using the browser's cryptographically secure random source. Copy the whole batch with one click.

100% client-side · nothing is uploaded

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How to use the UUID

Choose UUID v4 or ULID and how many you need.
Click Generate to create the identifiers.
Click Copy to copy the whole batch.
Generate again any time for fresh, cryptographically random values.

Privacy: this tool runs entirely in your browser. Your input is never sent to, received by, or stored on any server — there are no uploads and no tracking of what you enter.

About UUID

What is a UUID?

A UUID (Universally Unique Identifier) is a 128-bit value written as 32 hex digits in five groups. Version 4 UUIDs are random, making collisions astronomically unlikely — ideal for primary keys and request IDs.

What is a ULID?

A ULID is a 26-character identifier that is lexicographically sortable by creation time (the first part is a timestamp) while remaining globally unique. It's a popular alternative to UUID v4 when you want time-ordered IDs.

Randomness source

Both use crypto.getRandomValues / crypto.randomUUID, so the values are cryptographically secure, not predictable like Math.random().

Frequently asked questions

Are these UUIDs really unique?

Version 4 UUIDs have 122 random bits, so the chance of a collision is negligible for any realistic volume.

Can I generate many at once?

Yes — set the count (up to 1000) and copy them all with the Copy button.

UUID or ULID — which should I use?

Use ULID when you want IDs that sort by time (e.g. for database locality); use UUID v4 when you just need random uniqueness.