RSRobince Studio

UUID Generator

Create cryptographically random UUID v4 identifiers for databases, APIs and test data. Generate up to 500 at once.

Runs in your browser. Your files are never uploaded.

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How to use UUID Generator

  1. Enter how many UUIDs you need.
  2. Choose uppercase or hyphen options.
  3. Press Generate new and copy all.

What a UUID looks like

A UUID is 32 hexadecimal digits in five groups separated by hyphens: 8-4-4-4-12. In version 4, 122 of the 128 bits are random, and a few bits mark the version (the first digit of the third group is always 4) and variant. That structure lets different systems create identifiers independently without coordinating.

Where UUIDs are used

  • Primary keys in distributed databases, where an auto-increment number would clash between servers.
  • Public IDs in URLs that should not reveal how many records exist.
  • Idempotency keys for payment and API requests.
  • File names, session IDs and test fixtures.

Tips

Store UUIDs in a native UUID or 16-byte binary column when your database supports it; a text column takes more than twice the space. Be aware that random UUIDs fragment database indexes, so very write-heavy tables sometimes use time-ordered variants such as UUID v7 instead.

UUID versions explained

Version 1 UUIDs combine a timestamp and a machine identifier, which makes them sortable but can reveal when and where they were created. Version 4, produced here, is purely random and the most widely used. Version 5 generates the same UUID every time from a name and a namespace, which is useful for stable identifiers. Newer version 7 UUIDs start with a timestamp so they sort by creation time while staying unpredictable, which suits database primary keys.

If an application simply needs a unique ID with no ordering requirements, version 4 is a safe default.

Why use this uuid generator tool

  • Secure randomness. Uses crypto.randomUUID from your browser.
  • Bulk. Up to 500 identifiers in one go.
  • Formatting. Uppercase and no-hyphen variants.

Frequently asked questions

What is a UUID?

A Universally Unique Identifier is a 128-bit value written as 32 hex digits, like 3b241101-e2bb-4255-8caf-4136c566a962. GUID is Microsoft’s name for the same thing.

Can two UUIDs collide?

With version 4, the chance is astronomically small: you would need to generate about a billion UUIDs per second for roughly 85 years to reach a 50% chance of one duplicate.

Are these safe to use as secrets?

They are random, but a UUID is an identifier, not a password or token. Use a proper secret generator for authentication.

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