UUID Generator

Configuration

Generated 0 UUIDs
Click "Generate" to create UUIDs
100% Client-Side • Zero Data Sent to Servers

Online UUID / GUID Generator

Generate cryptographically random UUID v4 and time-based UUID v1 identifiers individually or in bulk for software development and database seeding.

Local Processing & Data Privacy

All formatting, parsing, decoding, and validation executes entirely within your browser using modern Web APIs and JavaScript. Your tokens, JSON payloads, regex inputs, and queries never leave your computer.

About this Tool

A UUID (Universally Unique Identifier), also called a GUID (Globally Unique Identifier), is a 128-bit identifier standardized in RFC 4122. UUIDs enable distributed systems to generate globally distinct keys without central coordination.

DevRef's Online UUID Generator uses browser cryptographic randomness (crypto.randomUUID and Web Crypto API) to produce collision-resistant UUID v4 identifiers. You can configure uppercase or lowercase formatting, hyphens or no-hyphens, braces, and bulk generation for CSV fixtures or database migrations.

How to Use

  1. 1Choose Version: Select UUID v4 (cryptographically random, recommended for 99% of use cases) or UUID v1 (timestamp + node).
  2. 2Configure Formatting: Choose uppercase vs lowercase, hyphenated vs stripped format, or wrapped in curly braces.
  3. 3Specify Quantity: Set the quantity to generate single IDs or bulk batches (e.g. 10, 50, 100).
  4. 4Copy or Download: Click Copy to copy all generated UUIDs to your clipboard for your application.

Key Features

  • •Cryptographically secure randomness powered by the browser Web Crypto API
  • •RFC 4122 compliant UUID v4 and v1 generation algorithms
  • •Bulk generator output supporting up to hundreds of UUIDs at once
  • •Customizable formatting: hyphens, uppercase, lowercase, and curly braces
  • •100% private in-browser generation: generated UUIDs are never tracked or saved to a server

Frequently Asked Questions

Are these UUIDs cryptographically secure?

Yes. UUID v4 identifiers are generated using the browser's native window.crypto.randomUUID() API, which utilizes system-level cryptographically secure pseudorandom number generators (CSPRNG).

What is the probability of a UUID v4 collision?

UUID v4 has 122 random bits, yielding 5.3 x 10^36 possible values. The probability of a collision is negligible—generating 1 billion UUIDs every second for 85 years yields a roughly 1 in a billion chance of a duplicate.

What is the difference between UUID v4 and UUID v1?

UUID v4 is entirely random and does not leak machine information. UUID v1 is derived from the system timestamp and MAC address, which provides time-sortability but reveals creation time and hardware identity.

Related Guides, Cheatsheets & Recipes

UUID Regex Validation Recipe

Standard regular expressions for validating UUID v4 strings in code and input forms.

Online JSON Formatter

Format and test mock JSON payloads with your newly generated UUID keys.

Base64 Encoder & Decoder

Encode raw binary UUID bytes into URL-safe base64 strings.