UUID / GUID Generator

Generate cryptographically secure UUIDs (v4) instantly. Bulk generate up to 100 at once. 100% client-side.

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Frequently Asked Questions

What is a UUID?

A UUID (Universally Unique Identifier) is a 128-bit number used to uniquely identify information in computer systems. Version 4 UUIDs are randomly generated and have a negligible probability of collision.

What is the difference between UUID and GUID?

UUID and GUID (Globally Unique Identifier) are essentially the same thing. UUID is the standard term, while GUID is Microsoft's term. Both are 128-bit identifiers.

Are these UUIDs cryptographically secure?

Yes. This tool uses the Web Crypto API (crypto.getRandomValues) which provides cryptographically strong random values.

What Is a UUID and How Does It Work?

A UUID (Universally Unique Identifier) is a 128-bit label used to uniquely identify records, entities, and objects across computer systems without requiring a central registration authority. A standard UUID is represented as a 36-character string formatted in five hexadecimal groups separated by hyphens (e.g., 123e4567-e89b-12d3-a456-426614174000). Because the space of possible UUIDs is so vast (2¹²⁸ or roughly 3.4 × 10³⁸ identifiers), systems can generate them independently with a mathematically negligible risk of collision.

The Differences Between UUID Versions

The RFC 4122 specification defines several different versions of UUIDs, each optimized for different use cases:

UUID Version 1 (Time-Based): Generated using a combination of the system's MAC address and a high-resolution timestamp. While guaranteed to be unique, they leak the physical location of the machine and the exact generation time, presenting privacy risks.

UUID Version 3 & 5 (Name-Based): Generated by hashing a namespace identifier combined with a name string using MD5 (for v3) or SHA-1 (for v5). The same input always yields the same UUID, making them ideal for deterministic mappings.

UUID Version 4 (Random): Generated entirely using random numbers (excluding 6 fixed version and variant bits). Out of the 128 bits, 122 bits are fully random, making UUID v4 the most popular choice for modern databases, APIs, and microservices.

Are UUIDs and GUIDs the Same?

Yes. UUID (Universally Unique Identifier) and GUID (Globally Unique Identifier) refer to the exact same 128-bit identifier standard. The difference is primarily historical and terminology-based: "UUID" is defined by the IETF (RFC 4122) and is widely used in open systems (Linux, macOS, Java, Node.js), whereas "GUID" is the terminology Microsoft adopted for its COM, Active Directory, and SQL Server systems. Both follow the same structure and are completely compatible.

Are Version 4 UUIDs Cryptographically Secure?

The security of a Version 4 UUID depends entirely on the source of randomness (entropy) used to generate it. Standard programming functions like JavaScript's Math.random() are pseudo-random number generators (PRNGs) and are predictable, making them unsafe for generating identifiers that protect sensitive resources. CyberScryb's generator utilizes the **Web Crypto API** (crypto.getRandomValues) which taps into the operating system's entropy pool. This ensures that every generated UUID is cryptographically secure and suitable for tokens, keys, database primaries, and security-sensitive identifiers.

Why Browser-Side UUID Generation Is Safe

Many online tools generate UUIDs by communicating with a backend server. If you use those identifiers for API keys, secret database values, or session tokens, you are risking data leaks, as the remote server has a record of the generated values. Our tool generates UUIDs entirely client-side using local JavaScript execution. The identifiers never traverse the network or touch a server, ensuring absolute privacy for your dev environment and production codebases.