UUID Generator

Generate RFC4122 compliant Universally Unique Identifiers (UUIDs) for your applications. Fast, secure, and works offline in your browser.

Generate Multiple UUIDs

UUID Usage Tips

  • Use UUID v4 for general-purpose unique identifiers
  • UUID v1 includes timestamp information, useful for sorting
  • UUIDs are 128-bit numbers represented as 32 hexadecimal digits
  • UUIDs are globally unique across space and time
  • Perfect for database primary keys, API tokens, and session IDs
  • UUIDs generated here use cryptographically secure random numbers

What is a UUID?

A UUID (Universally Unique Identifier) is a 128-bit number used to uniquely identify information in computer systems. UUIDs are standardized by RFC 4122 and are designed to be unique across both space and time without requiring a central coordination authority.

UUIDs are commonly used as database primary keys, session identifiers, API tokens, and anywhere a guaranteed unique identifier is needed. They're so unique that the probability of generating duplicate UUIDs is negligible, even when generating billions of identifiers.

UUID Versions Explained

Version 4 (Random): This is the most commonly used UUID version. It generates identifiers using random or pseudo-random numbers. Our tool uses JavaScript's crypto.getRandomValues() to ensure cryptographically secure random generation. V4 UUIDs have 122 random bits, making collisions extremely unlikely.

Version 1 (Timestamp-based): V1 UUIDs are generated using the current timestamp and the machine's MAC address. They're useful when you need time-ordered identifiers, though they may expose information about when and where the UUID was generated.

FAQ

Yes, UUIDs are designed to be unique without requiring a central authority. The probability of generating a duplicate UUID v4 is approximately 1 in 5.3 × 10³⁶ (or 1 in 5.3 undecillion). In practical terms, you would need to generate billions of UUIDs per second for centuries to have even a tiny chance of collision.
For most use cases, UUID v4 is the best choice. It's simple, completely random, and doesn't leak any information about your system. Use v1 only if you specifically need timestamp-based ordering or need to extract the generation time from the UUID later.
Yes, UUIDs are excellent for database primary keys, especially in distributed systems. They allow you to generate unique identifiers without coordination between database instances. However, note that UUIDs are larger than sequential integers and may have a small performance impact on indexing.
A standard UUID is displayed as 32 hexadecimal digits in five groups separated by hyphens: 8-4-4-4-12 (e.g., 550e8400-e29b-41d4-a716-446655440000). The total length is 36 characters including hyphens. You can optionally remove hyphens for a 32-character string.
UUID v4 generated with cryptographically secure random numbers (like DevToolsPro.org does) are suitable for session tokens and similar use cases. However, for security-critical applications like password reset tokens, consider using dedicated security token generators with additional entropy and expiration mechanisms.
Yes! The UUID generator on DevToolsPro.org runs entirely in your browser using JavaScript. Once the page is loaded, you can generate UUIDs without an internet connection. No data is sent to any server.

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