UUID Generator: Create Unique Identifiers Online
Generate UUIDs (Universally Unique Identifiers) instantly with our free online UUID generator. Create Version 1 (timestamp-based) or Version 4 (random) UUIDs for databases, APIs, distributed systems, and more. All UUIDs are generated locally in your browser using cryptographically secure methods.
What is a UUID?
A UUID (Universally Unique Identifier) is a 128-bit identifier standardized by RFC 4122. UUIDs are designed to be unique across space and time without requiring a central registration authority. The probability of generating duplicate UUIDs is so low that it's considered negligible for practical purposes.
UUID Format
UUIDs are typically displayed as 32 hexadecimal digits, displayed in five groups separated by hyphens:xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx. For example: 550e8400-e29b-41d4-a716-446655440000
When to Use UUIDs
- Distributed Systems: Generate unique IDs across multiple servers without coordination
- Database Keys: Use as primary keys when auto-increment isn't suitable
- API Development: Track requests, sessions, and transactions uniquely
- File Management: Assign unique identifiers to files and documents
- Microservices: Correlate events across different services
UUID Version Comparison
Version 4 (Random): The most commonly used version. Generated using random or pseudo-random numbers. Provides maximum privacy as it contains no identifying information. Recommended for most use cases.
Version 1 (Timestamp): Generated using the current timestamp and MAC address. UUIDs are sortable by creation time, which can be useful for databases. However, it may expose the MAC address and creation time.
Frequently Asked Questions
Are UUIDs truly unique?
While theoretically possible to generate duplicates, the probability is astronomically low (approximately 1 in 2^122 for version 4). For practical purposes, UUIDs can be considered unique.
Which UUID version should I use?
Version 4 (random) is recommended for most use cases as it provides maximum privacy and unpredictability. Use Version 1 if you need sortable IDs or want to embed timestamp information.
Can I use UUIDs as database primary keys?
Yes, UUIDs are commonly used as primary keys, especially in distributed databases. However, they take more storage space than integers and may impact index performance in some databases.
Are these UUIDs cryptographically secure?
Yes, our generator uses the Web Crypto API's crypto.getRandomValues() for Version 4 UUIDs, providing cryptographically secure random numbers suitable for security applications.