UUID Generator

Each identifier is produced by crypto.randomUUID, the browser's own version-4 generator, backed by the platform CSPRNG. Where that method is missing, the fallback builds the same 8-4-4-4-12 template from crypto.getRandomValues, and sets the version and variant nibbles correctly. Either path draws from the operating system entropy pool, not from Math.random.

Batch mode produces 1, 5, 10 or 25 at a time, one per line, with a toggle for uppercase if your database convention wants it. The stats line records how many were generated and states the entropy honestly. 122 random bits, because 6 bits are fixed for the version field and 2 more for the RFC 4122 variant. Built-in extras. A format selector and a download-as-.txt action.

122 bits is the correct number to quote and the reason the format works. The probability of two independently generated v4 values colliding is negligible at realistic volumes, so a UUID can be used as a primary key, an idempotency token or a correlation id without asking a central authority for a range.

The values are unpredictable, which matters for anything a client might try to enumerate. Opaque session identifiers, file download tokens, password-reset references. Nothing here is stored, logged or transmitted, so an identifier that leaves your clipboard exists only in your application.

Version 4 is deliberately unordered. Because the bits are random, keys do not sort by creation time, which makes them a poor clustered index in some databases and rules out any range scan by recency. If you need time-sortable identifiers you want version 7, which this tool does not claim to produce.

A UUID is an identifier, not a secret with human meaning. 36 characters is unwieldy in a URL a user reads, and it is not a substitute for proper authorisation checks. Generated values live only in the page, so reloading loses anything you did not copy.

Typical use is seeding test data or filling a form you are designing. Generate a batch, copy the list, and paste rows into a fixture file, a migration or a spreadsheet of sample records. For a single key, generate one, copy it immediately and store it where your schema expects it.

For shorter, human-scale secrets look at Password Generator. For a stable fingerprint of known content use SHA-256 Generator instead, since a hash of the same input repeats while a UUID never does. Both often appear in the same row. An id plus a checksum.