About

UUID Generator

Generate UUID v4 identifiers

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About This Tool

A UUID (Universally Unique Identifier) is a 128-bit identifier that is globally unique without requiring a central registration authority. UUID version 4, the most common variant, generates identifiers using random numbers, producing values like 550e8400-e29b-41d4-a716-446655440000. UUIDs are widely used as primary keys in databases, request correlation IDs in distributed systems and microservices, session tokens for user authentication, and unique identifiers for resources in REST APIs. They are especially valuable in distributed architectures where auto-incrementing IDs are impractical due to coordination overhead. Our free online UUID v4 generator creates RFC 4122 compliant identifiers instantly. You can generate a single UUID or bulk generate up to 100 UUIDs at once, with options for uppercase, lowercase, and no-hyphen formats.

How to Use

  1. Click the "Generate" button to create a single UUID v4. Each UUID is generated using cryptographically secure random numbers, ensuring global uniqueness with an extremely low collision probability.
  2. To generate multiple UUIDs at once, use the bulk generate option and specify how many UUIDs you need, up to 100 per batch.
  3. Choose your preferred output format: lowercase (default), uppercase, or without hyphens. The no-hyphen format is useful when you need a compact 32-character hexadecimal string.
  4. Copy individual UUIDs or copy all generated UUIDs at once using the bulk copy button. You can also download the list as a text file for batch processing.

Frequently Asked Questions

UUID (Universally Unique Identifier) and GUID (Globally Unique Identifier) are essentially the same thing. GUID is the term used by Microsoft, while UUID is the standard term defined by RFC 4122 and used by most other platforms. Both refer to a 128-bit identifier designed to be unique across space and time. In practice, the terms are interchangeable.
UUID v4 has 122 random bits, giving it 2^122 (approximately 5.3 x 10^36) possible values. The probability of a collision is astronomically low. To have a 50% chance of even one collision, you would need to generate approximately 2.71 quintillion UUIDs. For virtually all practical purposes, UUID v4 can be considered unique.
UUIDs are commonly used as database primary keys (especially in distributed systems where auto-increment IDs are impractical), request tracing IDs in microservices, session identifiers, file names for uploaded content, and unique resource identifiers in REST APIs. They eliminate the need for coordination between systems when generating unique identifiers.
UUIDv4 values are generated using random numbers, making them extremely difficult to predict. The probability of guessing a specific UUIDv4 is approximately 1 in 5.3 × 10^36, which is considered cryptographically sufficient for most non-security applications.

Examples

Generate Database Primary Key

Create a unique identifier for a new database record

550e8400-e29b-41d4-a716-446655440000

Generate Request Correlation ID

Create a trace ID for tracking requests across microservices

7c9e6679-7425-40de-944b-e07fc1f90ae7

Bulk Generate UUIDs

Generate multiple UUIDs at once for batch operations

f47ac10b-58cc-4372-a567-0e02b2c3d479, 6ba7b810-9dad-11d1-80b4-00c04fd430c8

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