Version UUID v4 (Random) UUID v7 (Time-based)
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How to Use the UUID Generator

UUIDs (Universally Unique Identifiers) are 128-bit identifiers designed to be unique across space and time. This generator creates standards-compliant UUIDs you can use for database primary keys, distributed systems, and any scenario requiring guaranteed unique identifiers.

  1. Choose your UUID version—v4 for random IDs, v7 for time-ordered IDs.
  2. Set the count if you need multiple UUIDs at once (up to 100).
  3. Click "Generate" to create new UUIDs instantly.
  4. Copy individual UUIDs or use "Copy All" for bulk operations.

UUID v4 vs UUID v7

UUID v4 (Random)

Generated using random or pseudo-random numbers. 122 bits of randomness provide 5.3 × 10³⁶ possible values—collisions are statistically impossible in practice.

Best for: General-purpose unique identifiers, distributed systems without ordering needs, session IDs, temporary resources.

UUID v7 (Time-ordered)

Embeds a Unix millisecond timestamp in the first 48 bits, followed by random bits. This makes UUIDs sortable by creation time while maintaining uniqueness.

Best for: Database primary keys (better index performance), event logging, any system that benefits from chronological ordering.

When to Use UUIDs

Database Primary Keys

UUIDs make excellent primary keys for distributed databases. Unlike auto-increment IDs, you can generate UUIDs on any client without coordination. UUID v7 is preferred for better index locality.

API Resource IDs

UUIDs hide information that auto-increment IDs expose. Competitors can't guess your resource count or enumerate your IDs by incrementing.

Distributed Systems

Multiple servers can generate UUIDs independently without risk of collision. No central authority or coordination required.

File & Session Naming

Generate unique file names, upload identifiers, or session tokens without worrying about conflicts or predictability.

Frequently Asked Questions

Will UUIDs ever collide?

Theoretically yes, but practically never. With UUID v4's 122 bits of randomness, you'd need to generate 2.7 quintillion IDs before having a 50% chance of one collision. For all practical purposes, they're unique.

Should I use UUIDs or auto-increment IDs?

UUIDs excel in distributed systems and when ID secrecy matters. Auto-increment is simpler and more compact for single-database applications. UUID v7 offers a good middle ground with database-friendly ordering.

Are UUIDs case-sensitive?

The RFC specifies lowercase output, but most systems treat UUIDs as case-insensitive. Our generator produces lowercase UUIDs per the spec.

Why is UUID v7 better for databases?

UUID v7's timestamp prefix means new records are inserted near the end of the index rather than scattered randomly. This improves B-tree index performance and reduces page splits in databases.