> uuid | guid | generate <
// Generate universally unique identifiers (UUID/GUID) instantly
Cryptographic Random
UUID v4 uses crypto.getRandomValues() for cryptographically secure random generation. Your data never leaves your browser.
Batch Generation
Generate up to 100 UUIDs at once. Perfect for database seeding, testing, and development workflows.
Multiple Versions
Support for UUID v4 (random) and v1 (timestamp-based). Choose the version that fits your use case.
// ABOUT UUID GENERATION
How UUID Works:
UUID (Universally Unique Identifier) is a 128-bit identifier standardized by RFC 4122. UUID v4 uses 122 random bits providing 2^122 possible values. The 36-character format follows the 8-4-4-4-12 pattern with version and variant bits embedded.
Example:
550e8400-e29b-41d4-a716-446655440000
Common Use Cases:
- >Database primary keys and record identifiers
- >Distributed systems without central coordination
- >Session tokens and correlation IDs
- >File naming and resource identification
- >API request tracing and logging
>> frequently asked questions
Q: What is a UUID?
A: A UUID (Universally Unique Identifier) is a 128-bit number used to uniquely identify information in computer systems. It is also known as GUID (Globally Unique Identifier). The standard format is 8-4-4-4-12 hexadecimal characters separated by hyphens.
Q: What is the difference between UUID v4 and v1?
A: UUID v4 is generated using random or pseudo-random numbers, making it the most commonly used version. UUID v1 is based on the current timestamp and a node identifier, which means it can reveal when and where it was created. V4 is preferred for most applications due to its simplicity and privacy.
Q: What is the probability of UUID collision?
A: UUID v4 has 122 random bits, giving 2^122 (approximately 5.3 x 10^36) possible values. The probability of generating a duplicate is astronomically low — you would need to generate about 2.71 quintillion UUIDs to have a 50% chance of a single collision.
Q: What is the difference between UUID and GUID?
A: UUID and GUID are essentially the same thing. UUID (Universally Unique Identifier) is the term used in most standards and platforms, while GUID (Globally Unique Identifier) is the term commonly used in Microsoft technologies. They follow the same format and generation algorithms.
Q: What is RFC 4122?
A: RFC 4122 is the Internet standard that defines the UUID format, generation algorithms, and namespace conventions. It specifies five versions of UUIDs (v1 through v5) and establishes the 8-4-4-4-12 hexadecimal representation format.