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UUID Generator

100% Free

Generate cryptographically random RFC 4122 v4 UUIDs — single, bulk (up to 1000), with format options. 100% client-side.

crypto.randomUUID
Client-Side
RFC 4122
0 UUID v4s

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  title="UUID Generator">
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How to Use

  1. 1 Choose how many UUIDs you need (1 to 1000)
  2. 2 Pick a format — standard, no-hyphens, UPPERCASE, or {braces}
  3. 3 Click 'Generate New' to refresh — runs entirely in your browser
  4. 4 Copy individual UUIDs or copy the whole batch

Features

  • RFC 4122 v4 (random) UUIDs
  • Bulk generation up to 1000 at a time
  • Four output formats (standard, no-hyphens, uppercase, braces)
  • Uses crypto.randomUUID() — the browser's native CSPRNG
  • Each UUID has 122 random bits → effectively zero collision risk
  • 100% client-side

Why it Matters

Every database table needs a primary key. Every distributed system needs a unique identifier. Every test fixture needs a placeholder ID. UUIDs solve all three because they can be generated independently anywhere with negligible collision risk. A fast bulk-generator beats writing a Node script for each batch you need.

★★★★★

Use Cases

Database Primary Keys

Pre-generate IDs for seeding test data

Session Tokens

Use as session identifiers in cookies / API keys

Filename / S3 Keys

Avoid filename collisions when uploading user files

Frequently Asked Questions

What's the chance of two UUIDs colliding?
Negligible. v4 has 122 random bits = 5.3 × 10³⁶ possible values. Even generating 1 billion per second for 100 years has < 1 in a quadrillion chance of any collision.
Why v4 and not v1?
v1 includes the device's MAC address and timestamp — useless in a browser, and a privacy concern. v4 is fully random and the modern standard.
Is crypto.randomUUID() actually random?
Yes — it uses the browser's CSPRNG (cryptographically secure random number generator), the same source TLS uses for key generation. Don't use Math.random() for IDs.
Can I use UUIDs as primary keys in MySQL / Postgres?
Yes, both have native UUID column types. Postgres has the fastest UUID indexing; MySQL works too but stores as 16 bytes more efficiently than as a 36-char string.
What's the difference between UUID and GUID?
GUID is Microsoft's name for the same thing — they're interchangeable. The {braces} format is the Microsoft convention.
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How to Use UUID Generator
uuid

How to Use UUID Generator — Complete Guide

Learn how to generate UUID v4 identifiers in bulk for databases, APIs, and testing using Tools.Town's free UUID Generator.

8 May 2026

5 min read

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