UUID v4 Generator | RFC 4122 Secure Unique IDs (Bulk)
Generate RFC 4122–compliant random UUID v4 values securely using your browser’s cryptographic API. Supports bulk generation, hyphen/case customization, and local-only privacy.
How to Use This Tool
- 1
Select the number of UUIDs to generate (1–100).
- 2
Choose your preferred format: with or without hyphens, uppercase or lowercase.
- 3
Click 'Generate UUIDs' to produce secure UUIDs via the Web Crypto API.
- 4
Copy individual IDs, use Copy All, or download them as a .txt file.
Use Cases & Examples
Database Keys
Use as distributed, collision-free primary or foreign keys in databases.
API Tokens & Authentication
Generate unpredictable API keys, session IDs, and access tokens.
File & Directory Naming
Assign unique names to files, logs, and directories across systems.
Distributed Systems
Create independent unique IDs across services and servers without central coordination.
How UUID v4 Generation Works
UUID v4 is a 128-bit identifier with 122 bits of randomness. Version and variant bits are fixed according to RFC 4122.
This tool uses crypto.getRandomValues() to generate cryptographically secure random numbers directly in your browser.
The UUID format is xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx, ensuring global uniqueness and RFC compliance.
Frequently Asked Questions
Q.Can two UUIDs ever be the same?
A. UUID v4 uses 122 bits of randomness, giving ~5.3×10³⁶ possible values. The chance of collision is practically zero for any real-world use.
Q.What's the difference between UUID v1 and v4?
A. UUID v1 includes timestamps and MAC addresses, potentially revealing system info. UUID v4 is purely random and privacy-safe.
Q.Is it safe? Does it send data to a server?
A. No—everything runs locally using the Web Crypto API. Nothing is uploaded or stored.
Q.Can UUIDs be used as database primary keys?
A. Yes, UUIDs make great distributed database keys—unique across systems without coordination. However, they’re not sequential, so index fragmentation may occur.
Related Tools
Explore more developer tools
Browse All Tools