UUID v1 Generator
Generate time-based UUIDs with embedded timestamp
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NanoID
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6ba7b810-9dad-11d1-80b4-00c04fd430c8What is UUID v1?
UUID v1 combines a timestamp with the MAC address of the generating machine, creating identifiers that are both unique and chronologically sortable. The embedded timestamp represents 100-nanosecond intervals since October 15, 1582—the date of Gregorian calendar reform.
This version guarantees uniqueness across time and space: the timestamp ensures temporal uniqueness, while the MAC address ensures spatial uniqueness across different machines.
Why Use UUID v1?
UUID v1 excels when you need sortable identifiers that cluster by creation time. Database indexes perform better with sequential keys, and v1 UUIDs are roughly time-ordered. This reduces index fragmentation and improves insert performance.
The embedded timestamp also enables extracting creation time from any UUID v1—useful for debugging, auditing, and understanding data lineage without additional metadata fields.
How UUID v1 Works
UUID v1 construction per RFC 4122:
1. Get current timestamp (100-ns intervals since 1582) 2. Get clock sequence (random, incremented on clock regression) 3. Get node ID (usually MAC address or random) 4. Combine: time-low, time-mid, time-hi-and-version, clock-seq-hi-and-reserved, clock-seq-low, node
The version number (1) appears in the time-hi-and-version field.
Common Use Cases
- Time-series data with sortable IDs
- Event sourcing and audit logs
- Database tables benefiting from sequential inserts
- Systems requiring creation timestamp extraction
Pro Tip
Use UUID v1 when insert performance matters—sequential IDs reduce B-tree index page splits.
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