inyourbrowser.com

UUID generator

UUID generator is a data tool that produces RFC 9562 UUID v4 identifiers using the Web Crypto API. It generates single UUIDs, bulk batches of up to 100, and the nil UUID, with one-click copy or download. The tool runs in your browser.

Generated UUID

VERSION

Runs entirely in your browser

Dedicated pages

Direct links for each UUID type.

UUID v4 generator
Generate a random UUID v4 instantly using the browser's built-in crypto API. Just click and copy. All processing runs in your browser.
Bulk UUID generator
Generate multiple UUID v4 values at once, up to 100 at a time. Copy all, or download as a text file. Runs in your browser.
Nil UUID
Generate or copy the nil UUID (00000000-0000-0000-0000-000000000000), the all-zeros sentinel or default value for UUID-typed fields. Runs in your browser.
Random UUID generator
Generate a random version 4 UUID from your browser's cryptographic random number generator and copy it. See how to spot a v4 UUID by its digits.
Generate a list of UUIDs
Generate up to 100 random UUIDs at once. Copy all, or download as a plain text file. Free, runs in your browser.

How to generate a UUID

  1. Click "Generate" to create a new UUID v4 (or choose Bulk or Nil UUID in the side panel).
  2. The UUID appears in the output field instantly.
  3. Click "Copy" to copy it to your clipboard.
  4. Click Generate again for a fresh random UUID.

Common uses

  • Generating unique identifiers for database records without a central coordinator
  • Creating unique IDs for user sessions, transactions, or events in an application, switch to a SHA-256 or MD5 fingerprint when you need a deterministic value from input data instead
  • Producing test data with unique keys. Pair with random strong passwords when you also need fake credentials in the same fixtures

Technical specification

  • Algorithm or formula: UUID v4 as defined in RFC 9562 (IETF, 2024), which replaced RFC 4122. 122 random bits plus 6 bits encoding the version (4) and variant (10xx). Formatted as xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx hexadecimal digits.
  • Browser API or library: Web Crypto API (crypto.randomUUID() primarily; crypto.getRandomValues() as fallback). Backed by the operating system CSPRNG.
  • Input limits: Bulk mode generates up to 100 UUIDs per batch. No upper bound on lifetime generation count.
  • Output: Plain text UUID strings, one per line in bulk mode. Copyable to clipboard or downloadable as a .txt file.
  • Known limitations: v4 only; v1, v3, v5, and v7 are not currently generated by this tool. Collision probability is statistically negligible but non-zero.

Frequently asked questions

What is a UUID?
A UUID (Universally Unique Identifier) is a 128-bit identifier formatted as 8-4-4-4-12 hexadecimal digits. Version 4 UUIDs are randomly generated and are the most common type.
How unique is a UUID v4?
Extremely unique. With 2^122 possible values, the probability of generating a duplicate is astronomically small, effectively zero for any real-world use case.
Is my UUID generated on a server?
All generation runs in your browser using the built-in crypto.randomUUID() API (v4), or crypto.getRandomValues() in older browsers. Our servers are not involved at any point.
What is the difference between UUID versions?
v4 is randomly generated and the most common choice. v1 is time-based. v3 and v5 are name-based (deterministic). v7 combines a timestamp with randomness for sortable identifiers.

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Reviewed and tested September 30, 2026.