UUID Generator Misc tools
Configuration
API Usage Examples
// Generate UUID v4 in JavaScript
function uuidv4() {
return 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g, function(c) {
var r = Math.random() * 16 | 0, v = c == 'x' ? r : (r & 0x3 | 0x8);
return v.toString(16);
});
}
console.log(uuidv4());
import uuid
# Generate UUID v4
print(uuid.uuid4())
# Generate UUID v5 with namespace
namespace_uuid = uuid.NAMESPACE_DNS
name = 'example.com'
print(uuid.uuid5(namespace_uuid, name))
<?php
// Generate UUID v4
function guidv4() {
$data = random_bytes(16);
$data[6] = chr(ord($data[6]) & 0x0f | 0x40);
$data[8] = chr(ord($data[8]) & 0x3f | 0x80);
return vsprintf('%s%s-%s-%s-%s-%s%s%s', str_split(bin2hex($data), 4));
}
echo guidv4();
?>
# Generate single UUID
curl https://www.uuidgenerator.net/api/version4
# Generate multiple UUIDs
curl https://www.uuidgenerator.net/api/version4/5
Cryptographically Secure
Uses secure random number generation for UUID v4, ensuring unpredictability
Globally Unique
122-bit random values provide 5.3 x 10³⁶ possible UUIDs with negligible collision probability
Fast Generation
Generate thousands of UUIDs instantly in your browser without server calls
Professional UUID Generator Tool
Our UUID Generator creates universally unique identifiers (UUIDs) for various applications and development needs. Whether you're building databases, developing APIs, or need unique identifiers for any purpose, our tool generates cryptographically secure UUIDs that meet industry standards.
What is a UUID?
A UUID (Universally Unique Identifier) is a 128-bit number used to uniquely identify information in computer systems. Also known as GUIDs (Globally Unique Identifiers) in Microsoft systems, UUIDs are standardized by RFC 4122 and provide a way to generate unique identifiers without a central authority or coordination between parties.
UUID Versions Explained
Version 1 (Timestamp + MAC)
Based on timestamp and MAC address. Guarantees uniqueness across space and time but may expose MAC address and creation time. Use when chronological ordering is important.
Version 3 (MD5 Namespace)
Generated using MD5 hashing of a namespace and name. Deterministic - same input always produces same UUID. Use for backward compatibility when MD5 is acceptable.
Version 4 (Random)
Generated using random or pseudo-random numbers. Most commonly used version with 122 bits of randomness. Ideal for general-purpose unique identifiers.
Version 5 (SHA-1 Namespace)
Similar to v3 but uses SHA-1 hashing. Preferred over v3 for new applications. Deterministic and suitable for distributed systems.
Nil UUID
Special UUID with all bits set to zero (00000000-0000-0000-0000-000000000000). Used as a null value or placeholder.
Key Features of Our UUID Generator
- Multiple UUID Versions: Support for v1, v3, v4, v5, and nil UUIDs
- Bulk Generation: Create up to 1000 UUIDs at once
- Format Options: Standard, uppercase, no-hyphens, braces, URN, and base64
- Namespace Support: DNS, URL, OID, X.500, and custom namespaces for v3/v5
- Instant Generation: Client-side generation for speed and privacy
- Export Options: Download generated UUIDs as text file
- No Registration: Generate unlimited UUIDs without signing up
Common UUID Use Cases
Database Primary Keys
Replace auto-incrementing integers with UUIDs for distributed databases, preventing ID conflicts in multi-master replication.
API Development
Use UUIDs for resource identifiers in RESTful APIs, ensuring globally unique identifiers across services.
Session Management
Generate secure session tokens that are practically impossible to guess or predict.
File & Object Storage
Uniquely identify files, objects, or resources in cloud storage systems without naming conflicts.
Distributed Systems
Generate IDs independently on different nodes without coordination or collision risk.
Transaction Tracking
Track transactions, orders, or events across multiple systems with guaranteed unique identifiers.
UUID Format and Structure
A standard UUID is displayed as 32 hexadecimal digits in the format:
xxxxxxxx-xxxx-Mxxx-Nxxx-xxxxxxxxxxxx
- 8-4-4-4-12: Groups of 8, 4, 4, 4, and 12 hexadecimal digits
- M: UUID version (1-5)
- N: Variant bits (8, 9, A, or B for RFC 4122 UUIDs)
- 128 bits total: Providing 2^128 possible UUIDs
Choosing the Right UUID Version
Use Version 4 (Random) when:
- You need simple, random unique identifiers
- No requirement for deterministic generation
- Privacy is important (no MAC address exposure)
- Most common choice for general applications
Use Version 1 (Timestamp) when:
- Chronological ordering is important
- You need to extract creation time
- MAC address exposure is acceptable
- Generating on a single machine
Use Version 5 (SHA-1) when:
- Deterministic IDs are required
- Same input must produce same UUID
- Building distributed systems
- Namespace-based identification
UUID Security Considerations
- Unpredictability: Version 4 UUIDs use cryptographically secure random numbers
- No Sequential Pattern: Unlike auto-increment IDs, UUIDs don't reveal quantity or order
- Privacy: Version 1 exposes MAC address and timestamp - use v4 for privacy
- Collision Probability: Extremely low - generating 1 billion UUIDs per second for 100 years yields 50% collision chance
- URL Safety: Standard UUID format is URL-safe without encoding
UUID vs Other Identifier Systems
UUID Advantages:
- No central authority required
- Can be generated offline
- Globally unique across systems
- Fixed size (128 bits)
- Standardized format
When to Use Alternatives:
- Auto-increment: When sequential ordering is needed
- Short IDs: When human readability is important
- Custom schemes: For specific business requirements
- Timestamps: When time-based sorting is critical
Implementation Examples
UUIDs are supported across all major programming languages and databases:
- JavaScript: crypto.randomUUID() or uuid library
- Python: uuid module in standard library
- Java: java.util.UUID class
- SQL: UUID data type in PostgreSQL, MySQL 8.0+
- C#: System.Guid structure
- Go: Various UUID packages available
Best Practices for UUID Usage
- Storage: Store as native UUID type when available, or as CHAR(36)
- Indexing: Consider using binary format for better index performance
- Validation: Always validate UUID format before processing
- Documentation: Document which UUID version your system uses
- Consistency: Use the same UUID version throughout your application
- Testing: Include UUID generation in unit tests
Frequently Asked Questions
How unique are UUIDs really?
Version 4 UUIDs have 122 bits of randomness, making collisions astronomically unlikely. You'd need to generate billions of UUIDs to have even a tiny chance of collision.
Can UUIDs be predicted or guessed?
Version 4 UUIDs using cryptographically secure random generators cannot be predicted. Version 1 UUIDs can be partially predicted if the MAC address and approximate time are known.
Which UUID version should I use?
Version 4 (random) is recommended for most applications. It's simple, secure, and doesn't leak information about when or where it was created.
Are UUIDs good for database primary keys?
Yes, UUIDs work well as primary keys, especially in distributed systems. However, they use more storage than integers and may have slightly slower index performance.
Can I extract information from a UUID?
Version 1 UUIDs contain timestamp and MAC address. Version 3 and 5 are deterministic based on input. Version 4 contains no extractable information.