UUID & ULID Generator - Bulk & Secure

How the UUID Generator Works

1. 01Click Generate to create a new UUID v4
2. 02The UUID is generated using cryptographically secure randomness
3. 03Generate multiple UUIDs at once if needed
4. 04Copy any UUID to your clipboard with one click

When to Use UUIDs

UUIDs (Universally Unique Identifiers) are 128-bit identifiers that are virtually guaranteed to be unique across all systems without coordination. UUID v4 uses random generation and is the most commonly used version. They are ideal for database primary keys in distributed systems, API resource identifiers, and session tokens. The probability of a collision is astronomically low - about 1 in 5.3 billion billion.

When to Use a UUID Generator

Use UUIDs as database primary keys in distributed systems where auto-incrementing integers would collide, as API resource identifiers that don't reveal record counts, as session tokens and correlation IDs for request tracing, and as unique filenames for uploaded content. Use ULIDs when you need the sortability benefit of timestamps combined with uniqueness.

Common Use Cases

• —Generate database primary keys for distributed systems where auto-increment would collide Hash Generator - SHA-256, SHA-512 & More
• —Create unique API resource identifiers that don't reveal record counts or creation order
• —Generate correlation IDs for request tracing across microservices
• —Create unique filenames for uploaded content to prevent collisions and overwrites
• —Generate test data identifiers for development and QA environments Strong Password Generator - Secure & Random

Expert Tips

• ✻Use ULID instead of UUID when you need chronological sorting - the timestamp prefix enables ORDER BY without a separate created_at column
• ✻In PostgreSQL, use gen_random_uuid() for server-side UUID generation rather than generating in application code - it is faster and ensures consistency
• ✻When using UUIDs as URL parameters, consider lowercase format without hyphens for shorter, cleaner URLs

Frequently Asked Questions

What is the difference between UUID and ULID?→

UUID v4 is purely random (122 bits of randomness) and not sortable. ULID combines a 48-bit millisecond timestamp with 80 bits of randomness, making it chronologically sortable. ULIDs are ideal for database primary keys where insertion order matters.

Can UUIDs collide?→

Theoretically yes, but practically no. UUID v4 has 2^122 possible values. You would need to generate about 2.7 quintillion UUIDs to have a 50% chance of a single collision. For all practical purposes, UUID collisions do not happen.

Should I use UUIDs as database primary keys?→

UUIDs prevent ID enumeration attacks and work well in distributed systems. However, random UUIDs can fragment B-tree indexes. Consider ULIDs or UUID v7 (timestamp-ordered) for better database performance. For single-server applications, auto-incrementing integers are simpler.

Is this generator secure?→

Yes. UUIDs and ULIDs are generated using the Web Crypto API (crypto.getRandomValues), which provides cryptographically secure randomness. No data leaves your browser.