BYTETOOLS

UUID Generator

Generate 1–100 cryptographically random UUID v4 identifiers at once. Uppercase and hyphen-less options, per-item copy and copy-all. Free UUID generator.

What is the UUID Generator?

The ByteTools UUID Generator creates version 4 (random) UUIDs using your browser's cryptographically secure random number generator.

  • Cryptographically secure UUID v4 (RFC 4122)
  • Batch generation, 1 to 100 at a time
  • Uppercase and hyphen-less formatting options
  • Per-item copy, copy-all and download as .txt
  • Runs offline — no server, no rate limits
  • Uses crypto.randomUUID with a secure fallback

How to use the UUID Generator

  1. 1

    Choose how many UUIDs to generate (1–100).

  2. 2

    Toggle Uppercase or Remove hyphens to match your target format.

  3. 3

    Click Generate to create a fresh batch.

  4. 4

    Copy individual UUIDs, copy all, or download the list as a text file.

About the UUID Generator

The ByteTools UUID Generator creates version 4 (random) UUIDs using your browser's cryptographically secure random number generator. Generate a single ID or up to 100 at once, ready to paste into database seeds, test fixtures, API keys or config files.

Formatting options cover the common variants: standard lowercase with hyphens (the RFC 4122 canonical form), UPPERCASE for systems like SQL Server that display GUIDs in capitals, and a compact 32-character hyphen-less form for URLs and keys. Copy any single UUID or the whole batch with one click.

Generation happens entirely in your browser using crypto.randomUUID with a getRandomValues fallback — no server involvement means no logging, no rate limits and no network needed.

Frequently asked questions

What is a UUID v4?

A version 4 UUID is a 128-bit identifier generated almost entirely from random data — 122 random bits plus 6 fixed version/variant bits. It is written as 36 characters (32 hex digits and 4 hyphens), and the third group always starts with 4.

Can two UUID v4 values ever collide?

Theoretically yes, practically no. With 122 random bits you would need to generate about 2.7 quintillion UUIDs to reach even a 50% chance of a single collision. Real systems treat v4 UUIDs as globally unique without any coordination.

What's the difference between a UUID and a GUID?

Nothing meaningful — GUID (Globally Unique Identifier) is Microsoft's name for the same 128-bit format defined in RFC 4122. Microsoft tooling often displays GUIDs in uppercase or braces, which is why this generator offers an uppercase option.

Are UUIDs generated here cryptographically secure?

Yes. The tool uses crypto.randomUUID (or crypto.getRandomValues as a fallback), which draws from the operating system's CSPRNG. Still, UUIDs are identifiers, not secrets — don't use them as passwords or session tokens on their own.

Should I use UUID v4 or v7 as a database primary key?

v4 works everywhere but its randomness scatters inserts across an index, which can hurt B-tree performance at scale. The newer time-ordered v7 keeps keys roughly sequential and is preferred for high-volume tables when your stack supports it.

Is a UUID without hyphens still valid?

The canonical RFC 4122 text form includes hyphens, but the underlying value is just 16 bytes, so the 32-character hyphen-less form represents the same identifier. Many systems, like compact URL slugs or certain database storage schemes, prefer the shorter form.

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