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UUID Generator

Generate v4 UUIDs — cryptographically random

Free UUID v4 generator — cryptographically random

Toololis UUID Generator produces RFC 4122 compliant UUID v4 identifiers using the browser\'s native crypto.randomUUID(). Generate 1 to 1000 UUIDs at once. Choose lowercase, uppercase, hyphen-less, or brace-wrapped formats.

How to use this tool

  1. 1

    Set quantity

    Choose how many UUIDs you need — from 1 to 1000 at once.

  2. 2

    Pick format

    Standard hyphenated (<code>123e4567-e89b-12d3-a456-426614174000</code>), uppercase, or without hyphens.

  3. 3

    Generate & copy

    Click Generate, then Copy to get all UUIDs on your clipboard, one per line.

Use cases

  • Database primary keys — better than auto-increment for distributed systems
  • File upload names — avoid collisions
  • Session tokens / CSRF tokens — 122 bits of entropy is sufficient
  • API request IDs — trace requests across microservices
  • Event IDs — uniquely identify messages in queues
  • Anonymous user tracking — GDPR-friendly when not tied to personal data

Frequently Asked Questions

What is a UUID?
Universally Unique Identifier — a 128-bit number used to uniquely identify things in distributed systems. Collision probability is essentially zero. Common formats: UUIDv1 (time-based), UUIDv4 (random).
Which UUID version does this generate?
UUID v4 (random). We use crypto.randomUUID() which is cryptographically secure and draws from 122 bits of entropy (2122 possible values).
Are these UUIDs truly unique?
Practically yes. The probability of collision among 1 billion generated UUIDs is still negligible (roughly 10-18). Feel free to use them as primary keys, session tokens, or file names.
What's the difference between UUID and GUID?
GUID is Microsoft's name for UUID. They're the same thing — 128-bit identifiers. "UUID" is the standard term in RFC 4122.
Can I use these for security tokens?
UUID v4 has 122 bits of entropy — enough for CSRF tokens or session IDs. For API keys or JWT secrets, use our Password Generator (more characters, no hyphens).
Are these UUIDs stored?
No. Generation happens entirely in your browser. We do not log, store, or transmit any generated IDs.

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100% Privacy. This tool runs entirely in your browser. Your data is never uploaded to any server.