UUID Generator

What this generator does

A UUID generator writes a 128-bit identifier in the usual 8-4-4-4-12 hex form. This UUID generator produces version 4 values. Version 4 means the bits are random, with the version nibble set to 4 and the variant bits set to RFC 4122. It is not version 1 (time and node), not version 7 (time-ordered), and not a sequential counter dressed up as a UUID.

When the browser exposes crypto.randomUUID, that function is used. That API is defined to return a version 4 UUID. If the function is missing but crypto.getRandomValues is present, the page fills 16 bytes, forces the version and variant bits, and formats the hex. If neither API exists, generation stops with a status error instead of falling back to Math.random.

Use this page for a database key, a request ID, or a filename that must not collide in ordinary use. Do not treat a UUID as a secret. It is an identifier. If you needed a password, use the Password Generator. If you needed a short hex token without UUID formatting, use the Random String Generator.

How to use

1. Enter how many values you need, from 1 to 50.
2. Generate. Each line is one UUID.
3. Copy writes the box to the clipboard. Clear empties the box.

Keyboard users can press Enter from the count field. The count and the output have visible labels. Empty or non-numeric counts are errors. Values above 50 are refused so the box stays readable.

Example

A typical result looks like 550e8400-e29b-41d4-a716-446655440000 in shape: groups of 8, 4, 4, 4, and 12 hex digits. The third group starts with 4 because this page only emits version 4. Generate twice and you get different values. That is the point of a random UUID. HTML-looking text in the count field is rejected as not a number.

550e8400-e29b-41d4-a716-446655440000

That sample is a well-known illustration of the grouping, not a value this page stored. Your next click will not repeat it on purpose. If a form asked for 36 characters including hyphens, this is that form. If it asked for 32 hex digits and no hyphens, delete the hyphens after copy. The generator will not offer a second layout that silently drops them.

Limits

• Version 4 only. No v1, v5, or v7.
• At most 50 values per click.
• Not a namespace UUID and not a hash of a name.
• Work stays in this browser. Nothing is uploaded.

Write the UUID next to the job it identifies. Generating twenty extras “just in case” and pasting the wrong one is how tickets get attached to the wrong row. If the specification asked for a ULID or a snowflake, this is the wrong generator.

Collision risk for version 4 is negligible for ordinary application IDs. It is not zero in the mathematical sense, and this page will not claim otherwise. It also will not phone a uniqueness service. Local generation is the whole product.

The output is lowercase hex with hyphens. Some systems store UUIDs without hyphens. Strip them yourself if the column requires that. This page will not silently change the canonical form.