UUID Generator
Generate RFC 4122 compliant v4 (random) UUIDs in bulk.
Generated UUIDs
Click ⚡ Generate to create UUIDs
What is a UUID Generator — Version 4 (Random)?
A UUID (Universally Unique Identifier) is a 128-bit identifier standardised by RFC 4122. Version 4 UUIDs are randomly generated using cryptographically secure random numbers. With 122 bits of randomness, the probability of generating a duplicate is astronomically low — around 1 in 5.3×10³⁶.
Common Use Cases
Database primary keys for distributed systems
Session tokens and authentication identifiers
File naming to avoid conflicts across systems
Message IDs in event-driven architectures
Unique identifiers in APIs and microservices
Tips & Best Practices
UUID v4 is the most commonly used version for general-purpose unique IDs
Use lowercase UUIDs for database storage — they are more portable
Strip hyphens for compact storage (32 chars instead of 36)
UUID v4 does not encode any timestamp or machine info — it is purely random
Frequently Asked Questions
What is a UUID?▼
UUID stands for Universally Unique Identifier. It is a 128-bit label used to uniquely identify objects in computer systems without a central authority.
What is the difference between UUID v1 and v4?▼
UUID v1 is based on the current timestamp and MAC address. UUID v4 is completely random. v4 is preferred for privacy and security because it reveals no information about when or where it was generated.
Can two UUIDs ever be the same?▼
In theory yes, but the probability is so low it is considered impossible in practice. UUID v4 has 2^122 possible values — roughly 5.3 undecillion unique IDs.
Are these UUIDs cryptographically secure?▼
Yes — this tool uses the browser's Web Crypto API (crypto.getRandomValues) which is cryptographically secure.