UUID Generator – Create Universally Unique Identifiers
UUIDs (Universally Unique Identifiers) are 128-bit identifiers that guarantee uniqueness across different systems and time periods. The UUID Generator creates UUID v4 identifiers using cryptographically strong random number generation, ensuring each generated ID is unique and suitable for use in distributed systems, databases, APIs, and applications requiring unique identifiers.
Whether you're developing applications, working with databases, or need unique IDs for any purpose, this generator provides reliable, standard-compliant UUIDs instantly.
What is a UUID?
UUID (Universally Unique Identifier), also known as GUID (Globally Unique Identifier), is a standardized 128-bit identifier format. UUIDs are designed to be unique across time and space, requiring no central coordination for generation.
The standard UUID format is: xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx (36 characters including hyphens), where "4" indicates version 4 (random UUIDs) and "y" is one of 8, 9, a, or b.
UUID Versions
Version 4 (Random UUIDs)
This generator creates UUID v4 identifiers, which use random or pseudo-random numbers. Version 4 UUIDs are the most commonly used type and don't require any input data—they're generated purely from random values.
Advantages:
- No central coordination required
- Can be generated offline
- Suitable for most use cases
- Guaranteed uniqueness (extremely high probability)
Common Use-Cases
1. Database Primary Keys
UUIDs are often used as primary keys in distributed databases where auto-incrementing integers could cause conflicts. UUIDs allow independent database nodes to generate IDs without coordination.
2. API Identifiers
RESTful APIs use UUIDs to identify resources, making it easier to merge data from different sources and avoiding ID collisions in distributed systems.
3. Session IDs
Web applications use UUIDs for session identifiers, ensuring each session has a unique, non-guessable ID that's secure against enumeration attacks.
4. File Identifiers
UUIDs identify files in storage systems, allowing files to be referenced uniquely across different systems and avoiding naming conflicts.
5. Distributed Systems
In microservices architectures, UUIDs enable different services to generate unique identifiers independently without coordination, simplifying system design.
UUID Format & Structure
A UUID consists of 32 hexadecimal digits displayed in five groups separated by hyphens:
- Format: 8-4-4-4-12 hexadecimal digits
- Example: 550e8400-e29b-41d4-a716-446655440000
- Total Length: 36 characters (32 hex digits + 4 hyphens)
- Binary Size: 128 bits (16 bytes)
UUID vs. Other ID Types
UUID vs. Auto-Increment Integers
UUID Advantages:
- No coordination needed across systems
- Can't be guessed or enumerated
- Suitable for distributed systems
- No central point of failure
Integer Advantages:
- Smaller storage size
- Better index performance
- Easier to read and remember
Security Considerations
- Unpredictability: UUID v4 uses random values, making them hard to guess
- Non-Sequential: UUIDs don't reveal creation order or quantity
- Collision Resistance: Extremely low probability of duplicates
- Privacy: Don't expose internal system information
When to Use UUIDs
Use UUIDs when:
- Working with distributed systems or microservices
- Merging data from multiple sources
- Security requires non-guessable identifiers
- IDs need to be generated offline or independently
- Building public APIs where ID exposure is acceptable
Consider alternatives when:
- Performance is critical and storage space matters
- IDs must be human-readable or memorable
- Sequential ordering is important
- Working with very large datasets where index size matters
Database Considerations
Storage
UUIDs require 16 bytes of storage (128 bits), compared to 4-8 bytes for integers. For large tables, this can impact storage requirements.
Indexing
UUID indexes can be larger and potentially slower than integer indexes due to size and randomness. Consider using UUID v1 (time-based) for better index locality if needed.
Performance
While UUIDs are larger than integers, modern databases handle them efficiently. The benefits of uniqueness and distribution often outweigh storage costs.
Best Practices
- Use UUID v4: For most applications, random UUIDs (v4) are the best choice
- Store as Binary: Consider storing UUIDs as binary (16 bytes) rather than strings for efficiency
- Index Carefully: Index UUID columns that are frequently queried
- Validate Input: Validate UUID format when accepting them as input
- Don't Expose Internals: While UUIDs don't reveal information, avoid exposing internal system details
Conclusion
The UUID Generator provides a quick and reliable way to generate standard UUID v4 identifiers. Whether you're building distributed systems, working with databases, developing APIs, or need unique identifiers for any purpose, this tool generates cryptographically strong, universally unique identifiers that are suitable for production use.