UUID Generator

Generate random UUID v4 identifiers instantly. Bulk generation and one-click copy.

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Generated UUIDs

What is a UUID?

A UUID (Universally Unique Identifier) is a 128-bit identifier that is unique across both space and time. UUID v4 uses random numbers, giving a practically zero chance of collision (1 in 2^122).

Common Uses

Database Keys: Primary keys for distributed systems
API Identifiers: Resource IDs in REST APIs
Session Tokens: Unique session identifiers
File Names: Temporary or unique file naming

How to Use the UUID Generator

Choose how many UUIDs you want to generate. The tool supports bulk generation, so you can create anywhere from a single UUID to hundreds at once — perfect for seeding databases, generating test data, or assigning unique IDs to batch records.
Select the format options: toggle between uppercase and lowercase hex digits, and choose whether to include hyphens in the standard 8-4-4-4-12 format or output a compact 32-character hex string.
Click the Generate button. Each UUID is created using cryptographically secure random number generation directly in your browser, producing valid RFC 4122 version 4 UUIDs.
Copy individual UUIDs with one click, or copy all generated UUIDs at once using the bulk copy button. Generated UUIDs can be pasted directly into databases, configuration files, API requests, or code.

Understanding UUIDs and Unique Identifiers

A UUID (Universally Unique Identifier), also known as a GUID (Globally Unique Identifier) in Microsoft ecosystems, is a 128-bit identifier represented as a 36-character string in the format xxxxxxxx-xxxx-Mxxx-Nxxx-xxxxxxxxxxxx. The standard form uses hyphens to separate five groups of hex digits. Version 4 UUIDs — the most commonly used variant — rely on random number generation for 122 of the 128 bits, making collisions astronomically unlikely. The probability of two independently generated UUIDs being identical is approximately 1 in 2.71 × 10^18, which means you would need to generate over 2.7 quintillion UUIDs before reaching even a 50% chance of collision.

UUIDs solve a fundamental problem in distributed systems: generating unique identifiers without a central authority or coordination between nodes. Unlike auto-incrementing integers, which require a single database to assign IDs sequentially, UUIDs can be generated independently by any client, server, or device. This makes them ideal for offline-first applications, microservices architectures, decentralized databases, and systems where multiple sources need to create records simultaneously. UUIDs are used extensively in database primary keys, API authentication tokens, file naming, session management, and distributed tracing systems like OpenTelemetry.

This generator produces RFC 4122 version 4 UUIDs using the Web Crypto API's crypto.getRandomValues() function, which provides cryptographically strong random values. Unlike Math.random(), which uses a simple pseudorandom algorithm unsuitable for security-sensitive applications, crypto.getRandomValues() draws from the operating system's entropy pool. This ensures that generated UUIDs are not only unique with overwhelming probability but also unpredictable — a critical requirement when UUIDs are used as session tokens, API keys, or any context where guessability could be exploited.

Frequently Asked Questions

Are these cryptographically secure?

Yes, they use crypto.getRandomValues() which provides cryptographically secure random numbers.

What is the difference between UUID and GUID?

They are essentially the same thing. GUID is Microsoft's term; UUID is the standard term.

Can UUIDs collide?

The probability of collision for UUID v4 is 1 in 5.3×10^36. It's safe to assume uniqueness.

Are generated UUIDs truly unique?

UUID v4 identifiers are random 128-bit values with 122 bits of entropy. The collision probability is so low (approximately 1 in 2.7 quintillion per pair) that for all practical purposes they are unique. No central registry or coordination is needed.

Can I use these UUIDs as database primary keys?

Yes. UUIDs are widely used as primary keys in PostgreSQL, MySQL, MongoDB, and many other databases. They work particularly well in distributed systems where records may be created on different servers before synchronization.

What is the difference between UUID and GUID?

There is no practical difference. UUID is the term defined by IETF RFC 4122, while GUID is Microsoft's name for the same concept. Both follow the same 128-bit format and the same generation rules.

Is it safe to use these UUIDs for security purposes?

This generator uses the Web Crypto API for cryptographically strong randomness, making the output suitable for session tokens, API keys, and other security contexts. However, always follow your organization's security guidelines for production systems.