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
- UUID v7 is time-ordered and better for database indexing than v4
- 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.
Read more about How to Generate Unique UUIDs Instantly — A Complete Guide for Developers
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.
Version 7 (Time-ordered): V7 UUIDs are a newer specification that combines the benefits of time-ordering with better database performance. They use Unix timestamps in milliseconds (48 bits) combined with random data. V7 UUIDs are lexicographically sortable by generation time, making them excellent for database primary keys where you want chronological ordering without the privacy concerns of v1.