UUID Generator
Generate various types of UUIDs (Universally Unique Identifiers) for your applications. Choose from different versions based on your specific needs.
UUID v6 (Timestamp Reordered)
Generate timestamp-based UUIDs with reordered fields from v1. Combines MAC address and timestamp but with improved field ordering for better database indexing.
Bulk Generation
Generate multiple UUIDs at once for batch operations
Only 1 to 10,000 allowed
API Information
Use these endpoints to integrate UUID generation into your applications
https://fastweb.tools/api/uuid/v6
Generate a single v6 UUID
https://fastweb.tools/api/uuid/v6?count=100
Generate multiple v6 UUIDs (max: 10,000)
What is UUID v6? Timestamp Reordered
UUID v6 (version 6) is an improved version of UUID v1 that reorders the timestamp fields to make the UUIDs naturally sortable by creation time. It maintains the same timestamp and MAC address components but arranges them for better performance.
Key Improvements over v1:
- Most significant timestamp bits come first
- Natural lexicographic sorting by creation time
- Better database index performance
- Reduced index fragmentation
Structure:
- Timestamp (high): 32 bits of high timestamp
- Timestamp (mid): 16 bits of middle timestamp
- Version + Timestamp (low): 4-bit version + 12-bit low timestamp
- Clock sequence: 14-bit sequence
- Node ID: 48-bit MAC address
Example Format:
1ec9414c-232a-6b00-b3c8-9e6bdeced846
When to Use UUID v6
✅ Ideal For:
- Database primary keys requiring time ordering
- Applications needing both uniqueness and sorting
- Migration from UUID v1 with performance improvements
- Systems requiring timestamp-based partitioning
- Event logging and audit trails
- Distributed systems with chronological requirements
❌ Avoid When:
- Privacy concerns about MAC address exposure
- High security requirements (predictable pattern)
- MAC address is not available or changes frequently
- Simple random identifiers are sufficient
Performance Benefits:
Significantly better database performance than v1 due to natural sorting order. Reduces B-tree index fragmentation and improves insertion speed.
Comparison: UUID v6 vs Alternatives
vs UUID v1
v6 provides the same uniqueness guarantees as v1 but with better performance due to timestamp reordering. Direct upgrade path from v1.
vs UUID v4
v6 offers time-based sorting that v4 lacks, but at the cost of reduced privacy and security due to MAC address inclusion.
vs UUID v7
v7 provides similar performance benefits but uses Unix timestamps and random data instead of MAC addresses, offering better privacy.
Migration Considerations
When migrating from UUID v1 to v6, existing v1 UUIDs will sort correctly with new v6 UUIDs when using proper timestamp-aware sorting algorithms. However, lexicographic sorting will not maintain chronological order between v1 and v6 UUIDs due to the field reordering.
Implementation Status
UUID v6 is part of the RFC 4122 update (draft) and gaining adoption. Most modern UUID libraries support v6 generation. Check library support before implementing in production systems.