UUID / GUID Generator
Generate cryptographically secure RFC 4122 UUID v4 in your preferred format (32/36/64 chars)
Select your format (36/32/64 chars) and click "Generate UUID" to create secure identifiers
Free Online UUID v4 Generator – Choose 32, 36, or 64 Characters
What is UUID and Why Use Different Lengths?
UUID v4 (Universally Unique Identifier version 4) is a 128-bit random identifier standardized by RFC 4122. Our tool generates true cryptographically-secure UUIDs using browser's crypto.randomUUID() (or secure fallback).
UUID Format Comparison (Industry Standards):
| Format | Length | Use Cases | Example |
|---|---|---|---|
| Standard (36 chars) | 36 chars (w/ hyphens) | RFC 4122, PostgreSQL, APIs, Java, .NET GUID | 550e8400-e29b-41d4-a716-446655440000 |
| Compact (32 chars) | 32 chars (no hyphens) | MySQL BINARY(16), MongoDB _id, REST APIs, URLs | 550e8400e29b41d4a716446655440000 |
| Double Hex (64 chars) | 64 chars | Redis keys, Cassandra, custom NoSQL, cache systems | 550e8400e29b...440000 (×2) |
Best Industry Practices – When to Use Each:
- 36-char Standard: Default choice. Use for PostgreSQL UUID type, Java
UUID, .NETGuid, JSON APIs - 32-char Compact: Space-efficient. Perfect for MySQL
CHAR(32)orBINARY(16), URL-safe IDs, microservices - 64-char Double: Legacy systems, Redis keys (
SET uuid_key:550e...), some NoSQL where full 128-bit hex needed as string
Real-World Use Cases
- Database Primary Keys: PostgreSQL
UUID, MySQLCHAR(36), MongoDB - API Identifiers: User IDs, order IDs, session tokens (32-char URL-safe)
- Microservices/Distributed Systems: Event sourcing, message queues
- Cache/Redis Keys: 64-char for namespaced unique keys
- Testing/Development: Mock data generation
Key Features
- ✔ 3 Formats: 36-char standard, 32-char compact, 64-char double hex
- ✔ Bulk up to 500 UUIDs instantly
- ✔ Uppercase option for consistency
- ✔ Crypto-secure using
Web Crypto API - ✔ 100% client-side – no data leaves browser
- ✔ Collision-free for practical purposes (1 in 2¹²² for 32/36-char, 1 in 2²⁴⁴ for 64-char)
Industry Recommendation: Use 36-char standard for new projects (universal compatibility). Choose 32-char for space optimization in production databases.64-char only for specific legacy/cache requirements.