Development Tools

UUID Generator

Create up to 1,000 random UUID version 4 identifiers in the browser with the native cryptography API, one canonical lowercase value per line.

Runs in your browserNever uploaded to PagesTools.
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100% privateYour input stays on this deviceLightning fastNo upload round-tripBrowser-basedProcessing runs on this deviceFree to useNo account required

What UUID Generator does

UUID Generator uses crypto.randomUUID when available. Its fallback draws 16 cryptographic random bytes, sets the version nibble to 4 and the RFC variant bits, then formats the bytes in the familiar 8-4-4-4-12 hexadecimal layout.

Version 4 UUIDs are probabilistically unique rather than checked against a central registry or your database. Their large random space makes accidental collisions unlikely for ordinary use, but a UUID is still an identifier, not proof of authorization or secrecy.

How to use UUID Generator

  1. Enter a whole result count from 1 through 1,000.
  2. Select Generate UUIDs to request fresh browser cryptographic randomness.
  3. Copy or download the one-UUID-per-line result.
  4. Apply uniqueness constraints and authorization checks in the destination system rather than trusting format alone.

Important details

Version and variant bits

The fallback explicitly marks UUID version 4 and the standard variant before formatting. These fixed bits identify the layout while the remaining bits come from Web Crypto.

Identifiers are not credentials

A UUID can label records without coordinating a sequence, but possession of one must not grant access by itself. It should not replace a password, token, signature, or database constraint.

Practical uses

  • Create identifiers for local fixtures, prototypes, or migration staging.
  • Generate client-side correlation IDs for development testing.
  • Prepare batches of version 4 UUID values for sample data.

Privacy and limitations

UUID generation happens locally and values are not sent to PagesTools. Once copied into a service, that service's storage and logging rules apply.

The tool provides no deterministic namespace mode, version 1, version 5, version 7, collision registry, database insertion, or access control. Web Crypto support is required, and no batch can exceed 1,000 values.

Common questions

Frequently asked questions

Which UUID version does this generator create?

It creates random version 4 UUIDs with the standard variant bits. Other time-based, name-based, and sortable UUID versions are not available here.

Are generated UUIDs guaranteed never to collide?

No finite random identifier can provide an absolute guarantee. Collisions are extremely unlikely in ordinary version 4 use, but a database should still enforce uniqueness where it matters.

Can a UUID be used as a secret access token?

Do not assume so. UUID format identifies a value but provides no permission model, expiry, signature, or storage protection. Use a security design intended for access tokens.