🆔 UUID/GUID Generator
Generate unique identifiers (UUID/GUID) in multiple formats. Support for UUID v1 (time-based) and v4 (random). Free online UUID generator with export options.
Random UUIDs - best for most use cases, completely unpredictable
What is a UUID?
A UUID (Universally Unique Identifier) is a 128-bit identifier that is guaranteed to be unique across time and space. UUIDs are also known as GUIDs (Globally Unique Identifiers) in Microsoft systems. They are standardized by RFC 4122 and are widely used in software development for identifying resources, database records, distributed systems, and more.
UUIDs are represented as 32 hexadecimal digits, displayed in five groups separated by hyphens: 8-4-4-4-12, for a total of 36 characters (32 hex characters + 4 hyphens). For example:550e8400-e29b-41d4-a716-446655440000
UUID Versions Explained
UUID v4 (Random)
UUID v4 uses random or pseudo-random numbers to generate identifiers. This is the most commonly used version because it provides excellent uniqueness guarantees without requiring coordination between systems.
Best for:
- Most general-purpose applications
- When you need unpredictable IDs
- Distributed systems without coordination
- Primary keys in databases
UUID v1 (Time-based)
UUID v1 includes a timestamp and MAC address (or random node ID) in its generation. This makes UUIDs sortable by creation time and can be useful for debugging and chronological ordering.
Best for:
- When you need chronological ordering
- Debugging and logging systems
- Time-sensitive applications
- When MAC address info is useful
Common Use Cases for UUIDs
💾 Database Primary Keys
UUIDs are excellent for primary keys in distributed databases where you can't use auto-incrementing integers. They prevent collisions when merging data from different sources.
🌐 API Identifiers
Use UUIDs as resource identifiers in REST APIs. They're opaque, don't reveal internal structure, and work well across different systems and services.
📦 File and Session IDs
Generate unique file names, session tokens, transaction IDs, and other temporary identifiers. UUIDs ensure no conflicts even in high-concurrency scenarios.
🔗 Distributed Systems
In microservices and distributed architectures, UUIDs allow different services to generate identifiers independently without coordination, reducing coupling and improving scalability.
Key Features of Our UUID Generator
Multiple Versions
Generate UUID v1 (time-based) or v4 (random) identifiers. Choose the version that best fits your use case.
Multiple Formats
Output UUIDs in standard format, without dashes, uppercase, with braces, or with brackets. Compatible with various systems and requirements.
Batch Generation
Generate up to 100 UUIDs at once. Perfect for bulk operations, testing, or when you need multiple identifiers quickly.
Export Options
Copy individual UUIDs or all at once. Export to a text file for easy integration into your projects or documentation.
Format Validation
All generated UUIDs are validated to ensure they conform to RFC 4122 standards. Visual indicators confirm valid UUID format.
Privacy First
All UUID generation happens locally in your browser. We never see, store, or have access to any generated identifiers.
Frequently Asked Questions
What's the difference between UUID v1 and v4?
UUID v4 uses random numbers and is completely unpredictable, making it ideal for most applications. UUID v1 includes a timestamp and can be sorted chronologically, which is useful for debugging and time-based ordering. Both are unique, but v4 is more commonly used.
Are UUIDs really unique?
While technically not guaranteed to be unique (the probability of collision is extremely low), UUIDs are designed to be unique for all practical purposes. The chance of generating two identical UUID v4s is approximately 1 in 5.3 × 10³⁶, which is effectively zero for most use cases.
Can I use UUIDs as database primary keys?
Yes! UUIDs are excellent for primary keys, especially in distributed systems. However, be aware that they take more storage space (16 bytes vs 4-8 bytes for integers) and may have slightly lower performance for indexing compared to sequential integers.
What format should I use?
The standard format (with hyphens) is most common and recommended. Use "no dashes" if your system requires it. Uppercase format is sometimes required by certain databases or systems. Braces and brackets are used in some Microsoft technologies (GUIDs).
Do you store the generated UUIDs?
No, absolutely not. All UUID generation happens entirely in your browser using JavaScript. We never see, store, transmit, or have any access to the UUIDs you generate. Your privacy is guaranteed.
How many UUIDs can I generate at once?
You can generate up to 100 UUIDs in a single batch. If you need more, simply generate another batch. There are no limits on the total number of UUIDs you can generate.