What is a UUID?
A UUID (Universally Unique Identifier), also known as a GUID (Globally Unique Identifier), is a 128-bit number used to uniquely identify information in computer systems. UUIDs are standardized by the Open Software Foundation (OSF) as part of the Distributed Computing Environment (DCE).
A UUID is typically represented as 32 hexadecimal digits displayed in five groups separated by hyphens, in the form: xxxxxxxx-xxxx-Mxxx-Nxxx-xxxxxxxxxxxx
How to Use This UUID Generator
- Click Generate to create a single UUID v4 instantly.
- Adjust the quantity slider to generate up to 100 UUIDs in bulk.
- Click Copy to copy one ID or the full list to your clipboard.
- Paste the UUID into your database schema, API request, or test fixture.
Worked Example
You need a primary key for a new user record in PostgreSQL. Click Generate and you might get:
Generated UUID v4
f47ac10b-58cc-4372-a567-0e02b2c3d479SQL usage
INSERT INTO users (id, name) VALUES ('f47ac10b-58cc-4372-a567-0e02b2c3d479', 'Ada');Common Use Cases
🗄️ Database Primary Keys
Use UUIDs as primary keys in distributed databases to avoid ID conflicts.
🔐 Session Tokens
Generate unique session identifiers for user authentication systems.
📁 File Naming
Create unique filenames to prevent overwrites and collisions.
🌐 Distributed Systems
Ensure unique identifiers across multiple servers without coordination.
🔗 API Request IDs
Track and trace individual API requests and transactions.
📦 Message Queues
Uniquely identify messages in distributed messaging systems.
UUID Version 4 (Random)
UUID v4 is the most commonly used version. It generates identifiers using random (or pseudo-random) numbers. The algorithm ensures that the probability of generating duplicate UUIDs is extremely low.
Key Characteristics:
- Uses 122 random bits (6 bits are used for the version and variant)
- Extremely low probability of collision (collision chance ≈ 1 in 2¹²²)
- No need for central coordination or time-based components
- Can be generated independently on any system
Frequently Asked Questions
What is UUID v4?
UUID v4 is generated from random numbers. It is the most common version for application IDs because it requires no central registry or timestamp coordination.
UUID v4 vs v7 — which should I use?
UUID v4 is random and works everywhere. UUID v7 is time-ordered, which can improve database index performance. Use v4 for general IDs; consider v7 when insert ordering matters at scale.
Can two UUIDs ever collide?
Theoretically yes, but the probability is astronomically low — roughly 1 in 2¹²² for v4. For practical purposes, collisions are not a concern.
Are browser-generated UUIDs cryptographically secure?
This tool uses crypto.getRandomValues(), which is suitable for non-guessable identifiers. Do not use UUIDs alone as authentication secrets or session tokens without additional validation.
Is UUID the same as GUID?
Yes. GUID is Microsoft's term for the same 128-bit identifier standard. The format and usage are identical.
Why Use Our UUID Generator?
🚀 Instant
Generate UUIDs instantly in your browser with no server delays.
🔒 Secure
Uses cryptographically strong random number generation.
📋 Bulk Generation
Generate up to 100 UUIDs at once for batch operations.
Fun Fact
If you generated 1 billion UUIDs every second, it would take about 100 billion years before you had a 50% chance of generating a duplicate UUID v4. That's longer than the current age of the universe!