What is a UUID?
A UUID (Universally Unique Identifier) is a 128-bit number used to identify information in computer systems. Our online UUID generator tools help you create these. The term GUID (Globally Unique Identifier) is also used and generally refers to UUIDs.
What are the different versions of UUIDs?
There are several versions of UUIDs, each generated using a different algorithm by a UUID generator. The most common versions you can generate are:
- Version 1: Time-based and MAC address-based.
- Version 3 & 5: Name-based (uses a namespace and a name).
- Version 4: Randomly generated.
- Version 6: Reordered time-based for better indexing.
- Version 7: Unix epoch timestamp-based with random bits.
Which UUID version should I use?
The best version depends on your specific needs:
- Version 4 is often preferred when you need a statistically unique identifier. Our UUID generator for Version 4 is ideal for this, as it doesn't rely on external dependencies or track generation order.
- Version 1 can be useful if you need some chronological ordering when you generate a UUID, and can accept the potential privacy implications of including a MAC address. Our Version 1 UUID generator provides this.
- Version 3 & 5 are useful for generating the same UUID for the same input (namespace and name). Version 5 uses SHA-1 hashing, which is generally preferred over MD5 (used by Version 3). You can use our UUID generator for these versions.
- Version 6 & 7 are newer time-based versions designed to improve upon Version 1's indexing issues.
Are UUIDs truly unique?
While the total number of possible UUIDs (2128) is extremely large, making collisions (when a UUID generator produces the same UUID twice) highly improbable, they are not guaranteed to be absolutely unique. However, for practical purposes, especially when you generate UUIDs with a good random source (like in Version 4), the probability of collision is negligible.
How can I generate a UUID on UUID.ca?
Our online UUID generator makes it easy. Simply navigate to the page for the specific UUID version you need (e.g., UUID Version 4 generator). Click the "Generate" or "Regenerate" button to create a new UUID. The generated UUID will be displayed, and you can copy it to your clipboard. For name-based versions like UUID Version 3 or 5, you'll need to provide a namespace and a name for the UUID generator.
How can I decode a generated UUID?
Use our UUID Decoder tool. Paste the UUID you want to analyze into the input field and click "Decode." The tool will attempt to identify the UUID version and extract any relevant information (like timestamp for Version 1, 6, and 7).
Do UUIDs contain any personal information?
Typically, randomly generated UUIDs (like Version 4) do not contain any personal information. When you generate a Version 1 UUID, it can potentially contain the MAC address of the generating device, which could be considered indirectly linked to a specific piece of hardware. Newer time-based versions like 6 and 7, which our UUID generator also supports, aim to mitigate these privacy concerns.
Can I use UUIDs for database primary keys?
Yes, UUIDs are often used as primary keys in databases. They offer several advantages when you generate UUIDs for this purpose, such as avoiding conflicts when merging data from different sources and making it easier to distribute databases. However, depending on the database system and the UUID version used (especially older versions like Version 1), there can be performance considerations related to indexing when you generate and use these UUIDs.
Where are generated UUIDs commonly used?
UUIDs generated by tools like our UUID generator are used in a wide range of applications, including:
- Database identifiers (especially when you need to generate unique IDs across systems)
- Distributed systems where a central ID generator isn't feasible
- Software development
- Tracking unique objects
- Content management systems
- API design
If you have any other questions, please feel free to contact us at [email protected].