Generate UUID online free. Create random UUID v4 identifiers and GUIDs with multiple output formats. Bulk UUID generation for databases, APIs, and development.
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Our UUID Generator creates random UUID v4 identifiers and GUIDs for developers, database administrators, and system architects. Generate unique identifiers for databases, APIs, microservices, and distributed systems with multiple output format options.
Choose from five output formats (standard, uppercase, no-hyphens, braces, URN) and generate up to 100 UUIDs at once. All UUID generation happens in your browser with no identifiers stored or transmitted.
Most commonly used UUID version. Generates random identifiers suitable for general-purpose use. Perfect for distributed systems, databases, and applications requiring unique identifiers without coordination.
Example: 550e8400-e29b-41d4-a716-446655440000Time-ordered UUIDs based on timestamp and MAC address. Useful for applications requiring chronological ordering of identifiers. Provides guaranteed uniqueness within the same system.
Example: 6ba7b810-9dad-11d1-80b4-00c04fd430c8Deterministic UUIDs generated from a namespace and name using SHA-1 hashing. Ideal for applications requiring consistent identifiers for the same input data across different systems.
Example: 6ba7b810-9dad-5d14-80b4-00c04fd430c8Support for various output styles: standard format, uppercase, no-hyphens, braces notation, and URN format. Choose the format that best fits your application requirements and coding standards.
Standard: 550e8400-e29b-41d4-a716-446655440000UUID (Universally Unique Identifier) and GUID (Globally Unique Identifier) are essentially the same thing. UUID is the standard term used in most programming languages and systems, while GUID is the Microsoft terminology. Both follow the same RFC 4122 specification and generate 128-bit unique identifiers.
Use UUID v4 (random) for most applications as it provides the best uniqueness guarantees. Use UUID v1 (time-based) when you need chronological ordering of identifiers. Use UUID v5 (name-based) when you need deterministic generation for the same input data across different systems.
While the probability of collision is extremely low (practically zero for most applications), UUIDs are not mathematically guaranteed to be unique. The 128-bit space provides 2^128 possible combinations, making collisions statistically improbable even with billions of generated UUIDs.
Yes, UUIDs make excellent primary keys, especially for distributed systems. They eliminate the need for coordination between database nodes and provide global uniqueness. However, consider that UUIDs are larger than integer keys and may impact performance in very large tables.
UUIDs are 16 bytes compared to 4-8 bytes for integers, so they use more storage. They can also impact index performance due to their random nature. For high-performance applications, consider using UUID v1 (time-based) or implementing proper indexing strategies.
Valid UUIDs follow the pattern: 8-4-4-4-12 hexadecimal characters separated by hyphens (e.g., 550e8400-e29b-41d4-a716-446655440000). You can use regular expressions or built-in validation functions in most programming languages to verify UUID format.
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