UUID Generator
Generate random UUIDs
UUID Version
Generated UUIDs
What is a UUID?
A UUID (Universally Unique Identifier) is a 128-bit identifier that's guaranteed to be unique across all devices and time, without requiring a central registration authority. UUIDs are used in distributed systems, databases, and applications where unique identification is critical.
UUIDs are also known as GUIDs (Globally Unique Identifiers), especially in Microsoft environments. They typically appear as 36 characters (including hyphens) in the format: 123e4567-e89b-12d3-a456-426614174000.
Common UUID Use Cases:
- Database Primary Keys: Ensures uniqueness across distributed databases
- Distributed Systems: Identifies resources without coordination
- Session IDs: Tracks user sessions securely
- Transaction IDs: Uniquely identifies transactions across systems
- Content Identifiers: Labels content in content management systems
UUID Version Comparison
Different UUID versions use different generation algorithms, each with specific advantages for particular use cases:
| Version | Generation Method | Advantages | Best For |
|---|---|---|---|
| UUID v1 | Time-based + MAC address |
| Logging, time-sensitive operations, sequential records |
| UUID v4 | Random generation |
| Most general purposes, security-sensitive applications, public identifiers |
| UUID v7 | Time-ordered + random |
| High-performance databases, time-ordered data, modern applications |
Our generator supports all three versions, allowing you to choose the right UUID type for your specific requirements.
UUID Implementation Examples
JavaScript
// Using crypto API
function generateUUIDv4() {
const bytes = new Uint8Array(16);
crypto.getRandomValues(bytes);
// Set version (4) in byte 6
bytes[6] = (bytes[6] & 0x0f) | 0x40;
// Set variant (10) in byte 8
bytes[8] = (bytes[8] & 0x3f) | 0x80;
return Array.from(bytes).map(b =>
b.toString(16).padStart(2, '0')
).join('').match(/(.{8})(.{4})(.{4})(.{4})(.{12})/).slice(1).join('-');
}
// Usage
const myUUID = generateUUIDv4();
console.log(myUUID);Python
import uuid
# Generate UUID v4 (random)
uuid_v4 = uuid.uuid4()
print(f"UUID v4: {uuid_v4}")
# Generate UUID v1 (time-based)
uuid_v1 = uuid.uuid1()
print(f"UUID v1: {uuid_v1}")Java
import java.util.UUID;
public class UUIDExample {
public static void main(String[] args) {
// Generate random UUID (v4)
UUID uuid = UUID.randomUUID();
System.out.println("UUID v4: " + uuid);
}
}Frequently Asked Questions About UUIDs
What's the difference between a UUID and a GUID?
UUIDs (Universally Unique Identifiers) and GUIDs (Globally Unique Identifiers) are essentially the same thing. GUID is Microsoft's implementation of the UUID standard. Both are 128-bit values designed to be unique across all devices and time. Our online UUID & GUID generator creates identifiers that work in any system.
Which UUID version should I use?
For most applications, UUID v4 (random) is recommended as it provides the highest level of uniqueness and privacy. If you need chronological sorting, consider UUID v7 for modern applications or UUID v1 for legacy systems. Our UUID generator for developers supports all three versions.
Are UUIDs truly unique?
While theoretically there's a possibility of collision (duplicate UUIDs), the probability is extremely low. A random UUID generator (v4) has 2^122 possible values. The chance of generating a duplicate is negligible for practical purposes, making UUIDs ideal for distributed systems and database applications.
How do I implement UUIDs in my database?
Most modern databases have native UUID data types. For optimal performance when using UUIDs as primary keys, consider using UUID v7 (time-based) which provides better indexing performance due to its time-ordered nature. You can generate UUID v7 online using our tool.
Can I create UUIDs offline?
Yes, most programming languages have libraries to create UUIDs without an internet connection. However, our online UUID generator is convenient for quick testing, documentation, and situations where you don't want to write code.