Online UUID Version 6 Generator

Generate Time-Ordered UUIDs
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UUID Version 6 Explained: Time-Ordered, Sortable, and Efficient

Welcome to UUID.ca's free web-based UUID Version 6 tool! If you need to generate unique identifiers that are also chronologically sortable, especially for optimizing database performance, UUIDv6 is an excellent choice. This tool allows you to instantly create UUID Version 6 identifiers, often referred to as "time-ordered UUIDs," compliant with modern standards.

What Exactly is a UUID Version 6?

UUID Version 6 (UUIDv6) is a type of Universally Unique Identifier designed to be time-ordered. It achieves this by reformatting the timestamp components of the older UUID Version 1. This reordering makes UUIDv6 values highly sortable, which is a significant advantage for database indexing and performance. When you generate a UUID Version 6, you're getting an ID that combines the global uniqueness properties of UUIDs with the benefits of sequential ordering.

The specification for UUID Version 6, along with other new UUID formats like Version 7, is detailed in RFC 9562. This standard builds upon the foundations of RFC 4122, which defines the original UUID versions. Our UUID generator adheres to these specifications to ensure compatibility and reliability.

Key Structural Components of UUIDv6:

  • Reordered Timestamp (60 bits): This is the core of UUIDv6's sortability. The timestamp, representing time in 100-nanosecond intervals since October 15, 1582 (the Gregorian epoch, same as UUIDv1), is rearranged. The most significant 48 bits of the timestamp (time_high and time_mid from v1) are placed at the beginning of the UUID, followed by the 4-bit version ('0110' for v6), and then the remaining 12 bits of the timestamp (time_low). This strategic placement by the UUID generator ensures that IDs generated closer in time will sort correctly.
  • Clock Sequence (14 bits): This field, as in UUIDv1, helps prevent collisions if the system clock is adjusted backward or if multiple UUIDs are generated too quickly for the timestamp to resolve. Our UUID generator manages this to ensure uniqueness when you generate UUIDs.
  • Node Identifier (48 bits): Traditionally, this was the MAC address of the generating machine. For privacy reasons, modern UUID Version 6 generators, including this online UUID generator, often use a high-quality random 48-bit number for this component. This avoids leaking hardware information while still contributing to the UUID's uniqueness.
  • Version and Variant Bits: As mentioned, the version bits are set to '6' (binary '0110'). The variant bits are set to '10xx' (specifically '10' for RFC 4122 compatibility), indicating the UUID's layout structure. This ensures the generated UUID Version 6 is standard-compliant.

The resulting format for a UUID Version 6 generated by our tool is typically xxxxxxxx-xxxx-6xxx-axxx-xxxxxxxxxxxx, where '6' denotes Version 6, and 'a' (or '8', '9', 'b') indicates the RFC 4122 variant. The '6' is a clear indicator that you've used a UUID Version 6 generator.

Why Generate UUID Version 6? The Advantages

Using a UUID Version 6 web generator offers several compelling benefits, particularly for developers and database administrators looking to generate UUIDs that are both unique and sortable:

  • Improved Database Indexing Performance: This is the primary advantage. When UUIDv6 values are used as primary keys (e.g., in PostgreSQL, MySQL, SQL Server), new records are inserted in a largely sequential manner. This helps maintain data locality on disk, reducing index fragmentation and improving the efficiency of B-tree indexes. Unlike purely random UUIDv4, which can cause scattered writes and frequent index page splits, UUIDv6 promotes more ordered writes. This leads to faster inserts and more efficient queries that filter or sort by the ID, a key benefit when you generate UUID version 6.
  • Chronological Sortability: Because the timestamp is at the beginning and ordered logically, UUIDv6 identifiers can be sorted chronologically without needing a separate timestamp column for this purpose. This is invaluable for time-series data, logs, activity feeds, and any scenario where retrieving records in their creation order is essential after you generate a UUID.
  • Global Uniqueness: Like other UUID versions, UUIDv6 aims for global uniqueness. The combination of a high-resolution timestamp, clock sequence, and a node identifier (even if random) makes the probability of collision extremely low when using a reliable UUID generator.
  • Transition from UUIDv1: For systems already using UUIDv1, migrating to or incorporating UUIDv6 can be relatively straightforward due to the shared structural elements (timestamp, clock sequence, node ID), with v6 offering superior sortability.

UUIDv6 vs. Other UUID Versions

When you decide to generate a UUID, understanding the differences between versions is key for choosing the right one for your needs. Our online UUID generator provides various versions, and here's how v6 compares:

When you decide to generate a UUID, understanding the differences between versions is key for choosing the right one for your needs. Our online UUID generator provides various versions, and here's how v6 compares:

  • UUIDv6 vs. UUIDv1: Both are time-based. However, UUIDv1's timestamp components are arranged in a way that doesn't lend itself well to direct lexicographical sorting (time_low-time_mid-time_hi_and_version). UUIDv6 reorders these (conceptually time_hi-time_mid-time_low_and_version, with version bits correctly placed by the UUID generator), making it sortable.
  • UUIDv6 vs. UUIDv4: UUIDv4 is entirely random (except for version and variant bits). This provides excellent collision resistance and privacy (no timestamp or MAC address). However, its randomness is detrimental to database index performance for clustered indexes. UUIDv6 offers sortability, a key difference when you generate UUID version 4 versus version 6.
  • UUIDv6 vs. UUIDv7: UUIDv7 is another modern, time-ordered UUID. It uses a simpler Unix Epoch timestamp (milliseconds) and a different bit layout, often favored for potentially better monotonicity guarantees and easier implementation. The choice between generating UUID Version 6 or Version 7 can depend on specific application needs, desired timestamp precision, and compatibility. Our platform also offers a UUID Version 7 generator if that better suits your requirements.

Common Use Cases for UUID Version 6

The properties of UUIDv6 make it suitable for a variety of applications where you need to generate unique IDs that are also time-ordered. This UUIDv6 online tool can be helpful for:

  • Database Primary Keys: Especially for large tables in systems like PostgreSQL or MySQL where insert order and time-based queries are common. Using a UUID Version 6 generator here can lead to significant performance gains.
  • Distributed Systems: Generating unique, sortable IDs across multiple nodes without a central coordinator.
  • Event Sourcing: Ensuring events are stored and can be easily retrieved and replayed in strict chronological order.
  • Logging and Tracing: Assigning sortable IDs to log entries or trace spans for easier debugging and analysis.
  • Time-Series Data: Ideal for records where the natural order is chronological, making the output of this UUID generator highly valuable.
  • Content Management Systems: Versioning articles, posts, or media with time-ordered identifiers.

Privacy Considerations When Generating UUIDv6

As with UUIDv1, if a real MAC address is used for the node identifier component, a generated UUID Version 6 could potentially reveal information about the machine that created it. To mitigate this, our online UUID generator typically uses a randomly generated 48-bit number for the node ID. This approach significantly enhances privacy while maintaining a very high probability of uniqueness for the generated UUID.

Using a random node ID means the "node" part doesn't tie back to specific hardware, making the UUIDs safer for public exposure or use in multi-tenant systems when you generate UUIDs.

Using Our UUIDv6 Online Tool

Generating a UUID Version 6 with our web utility is straightforward:

  1. Simply click the "Generate" button in the hero section above.
  2. A new, unique UUID Version 6 will instantly appear in the display area.
  3. You can then copy this generated UUID to your clipboard using the "Copy" button.

Each UUID created by this web-based UUIDv6 utility is fresh and adheres to the UUIDv6 specification, ready for your application. Whether you need one UUID or many, our tool provides a quick and reliable way to create UUIDs.

In summary, when your application requires identifiers that are not only unique but also sortable by time to enhance database performance or simplify data handling, generating UUID Version 6 is a robust and modern solution. This online UUID generator makes the process easy and accessible.