Bytelify

Random GUID Generator

Generate RFC 4122 v4 GUIDs/UUIDs instantly.

Runs in your browser, nothing sent
random-guid-generator
 
 
 
 
 

Generates RFC 4122 v4 UUIDs using crypto.randomUUID(), entirely in your browser.

Need the opposite? Random String Generator

What is Random GUID Generator?

Generates standards-compliant version-4 GUIDs (also called UUIDs) using your browser's built-in crypto.randomUUID(), the same cryptographically secure random source used by Node.js and modern databases, not a hand-rolled approximation.

How to Use the Random GUID Generator

  1. 1

    Generate a GUID: A UUID is generated automatically when the page loads, or click Generate for a new one.

  2. 2

    Copy the Result: Use the copy button to copy the GUID for a test database, mock API response, or correlation ID.

How It Works

Each click calls crypto.randomUUID(), your browser's built-in generator for version-4 UUIDs: the variant defined by RFC 4122 that's built almost entirely from random bits (122 of the 128 total, with the rest fixed to mark the version and variant). The result is formatted as five hyphen-separated groups, e.g. xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx. This uses the browser's native cryptographically secure random source rather than a hand-rolled random function, so the output has the same statistical quality as UUIDs generated by Node.js, PostgreSQL, or any other standards-compliant v4 implementation. It isn't a simplified approximation.

Common Use Cases

  • Primary keys or foreign keys in a test database, where you need unique-looking IDs without wiring up a real ID-generation service.

  • Mock API responses and fixture files that need a realistic-looking id field.

  • Correlation IDs for tracing a request through logs during local development or debugging.

FAQs

Frequently Asked Questions

Common questions about Random GUID Generator.

They're the same thing. GUID is Microsoft's name for what the rest of the industry calls a UUID, both referring to the same 128-bit identifier format.

Astronomically: a version-4 UUID has 122 random bits, so generating a billion per second for a hundred years would still leave the chance of any collision below 50%.

Yes, from a randomness standpoint; it uses the same crypto.randomUUID() API and v4 format that databases and backend frameworks rely on. Whether UUIDs are the right primary key choice at all (versus an auto-incrementing integer or a sortable ID scheme) is a separate database-design decision outside what this tool addresses.

In a v4 UUID, the third group always starts with the digit 4 (marking the version), and the fourth group's first character is always 8, 9, a, or b (marking the RFC 4122 variant). Those fixed bits are what's left of the 128 total after the 122 random ones.

Yes, Bytelify's Random GUID Generator is free with no account or sign-up required.

No. Generation runs entirely client-side via your browser's native crypto.randomUUID(), so nothing is sent anywhere.