What is a UUID / GUID?

A UUID (Universally Unique Identifier) or GUID (Globally Unique Identifier) is a 128-bit label used to uniquely identify resources in computer systems without requiring a central registration authority.

How unique is a Version 4 (v4) UUID?

Version 4 UUIDs use 122 bits of pseudo-randomness. The probability of generating a duplicate v4 UUID is so infinitesimally small (1 in 2^122 or ~5.3 x 10^36) that it is virtually impossible in practical computing.

Are generated UUIDs cryptographically secure?

Yes. Our tool uses the browser's native Web Crypto API (crypto.randomUUID / crypto.getRandomValues) to ensure cryptographically secure entropy.

Free Online UUID / GUID Generator | Cryptographically Secure

Q: Is this UUID generator free to use?

Yes, MicroToolStack's UUID Generator is 100% free with unlimited generation limits and no account registration required.

Quantity (1 to 100)

UUID Version

Include Hyphens (-) Uppercase (ABC...) Enclose in Braces ({...})

Understanding UUIDs (Universally Unique Identifiers) and GUIDs

A Universally Unique Identifier (UUID)—also referred to as a Globally Unique Identifier (GUID) in Microsoft ecosystems—is a 128-bit value formatted as 32 hexadecimal digits separated by hyphens (e.g. 123e4567-e89b-12d3-a456-426614174000).

The primary advantage of UUIDs is independence: distributed system architectures, microservices, and databases can generate billions of unique resource keys concurrently without consulting a central coordinating authority or risking primary key collisions. Our free Online UUID Generator utilizes Web Crypto entropy to deliver cryptographically secure Version 4 UUIDs instantly.

UUID Versions Overview: v1 vs. v3 vs. v4 vs. v5

While Version 4 is the most popular, standard specifications (RFC 4122) define multiple version types:

Version	Generation Method	Primary Use Case	Collision Risk
v1 (Time-Based)	Combines host MAC address + timestamp	Sequential event tracking	Negligible (Exposes MAC address)
v3 (MD5 Name)	MD5 hash of namespace + name string	Deterministic name mapping	Zero for identical inputs
v4 (Random)	122 bits of cryptographic randomness	Database primary keys & REST APIs	Virtually zero (~1 in 5.3x10^36)
v5 (SHA-1 Name)	SHA-1 hash of namespace + name string	Secure deterministic mapping	Zero for identical inputs

Features of MicroToolStack's UUID Generator

Cryptographically Secure Entropy: Uses browser native crypto.randomUUID() and crypto.getRandomValues() for true random distribution.
Bulk Generation Support: Generate from 1 to 100 UUIDs concurrently for seed scripts, unit tests, or database imports.
Custom Formatting Options: Easily toggle hyphens, uppercase casing, or wrapping braces ({...}).
100% Client-Side Privacy: All UUIDs generate locally inside your web browser session using JavaScript. No keys are logged or transmitted remotely.

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Frequently Asked Questions (FAQs)

What is a Version 4 UUID?

A Version 4 UUID is a 128-bit identifier generated using random numbers. It contains 122 bits of cryptographically secure randomness.

Can two generated v4 UUIDs ever collide?

The probability of two v4 UUIDs colliding is so small (1 in 5.3x10^36) that it is practically impossible in real-world computing environments.

Is my generated UUID stored on any remote server?

No. All generation logic runs client-side inside your web browser session using JavaScript. No generated keys are saved or transmitted.

Is this UUID Generator free to use?

Yes, MicroToolStack's UUID Generator is 100% free with no usage limits or sign-up required.