UUID v4 vs v7: Which Should You Use in 2026?
2026-07-12•6 min read
UUID v7 is time-ordered and indexed efficiently by database engines, making it superior to random UUID v4 for primary keys. Learn the architectural advantages of time-sorted IDs.
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UUID Version 4: Random Identifiers
- Random Generation
- Uses cryptographically secure pseudo-random numbers to yield 122 bits of entropy.
- Indexing Overhead
- Causes severe database index fragmentation in clustered indexes due to random insertion paths.
UUID Version 7: Time-Ordered Identifiers
- Unix Timestamp
- Includes a 48-bit millisecond timestamp in the prefix.
- Sequential Insertion
- Enables databases to write values sequentially, boosting index lookup and write speeds.
Frequently Asked Questions
Is UUID v7 supported in modern databases?
Yes, UUID v7 fits perfectly into any standard 128-bit UUID database column, such as PostgreSQL's UUID type.
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