UUID Generator
Generate UUIDs (v1, v4, v7) for unique identifiers
Generate Multiple UUIDs
About the UUID Generator
A UUID (Universally Unique Identifier), also known as GUID (Globally Unique Identifier), is a 128-bit identifier designed to be unique across all devices and all time without requiring a central registration authority. UUIDs are fundamental to distributed systems, database design, and modern software architecture.
The UUID Generator on UniversalDevTools.in supports three major UUID versions, each optimized for different use cases:
**UUID v1 (Time-based)** combines the current timestamp with the machine's MAC address. This creates sequential, time-ordered IDs but may expose your hardware identity—making v1 less suitable for security-sensitive applications.
**UUID v4 (Random)** is generated entirely from cryptographic random numbers, providing complete unpredictability with no embedded information. V4 is the most widely used version due to its simplicity and privacy, though IDs are not chronologically sortable.
**UUID v7 (Time-ordered)** is the newest standard, embedding a Unix timestamp in the first 48 bits while using random data for the remaining bits. V7 UUIDs are chronologically sortable, making them ideal for database primary keys where insertion order matters for index performance.
All UUID generation happens locally in your browser using the Web Crypto API. Your generated identifiers are never transmitted to servers, making this tool safe for generating production database keys, API resource IDs, and security tokens.
features
- Support for UUID v1 (time-based), v4 (random), and v7 (time-ordered)
- Bulk generation of up to 100 UUIDs at once
- Multiple output formats: lowercase, uppercase, no hyphens
- Time-ordered UUID v7 for optimal database indexing
- Cryptographically secure random generation
- One-click copy for individual or bulk UUIDs
- 100% client-side processing for complete privacy
use cases
- Creating primary keys for PostgreSQL, MySQL, and MongoDB databases
- Generating session tokens and authentication identifiers
- Creating unique filenames for cloud storage (S3, GCS, Azure Blob)
- Building distributed systems requiring collision-free identifiers
- API resource identification and URL slugs
- Generating correlation IDs for microservices tracing
- Creating unique transaction IDs for payment systems
why use it
- Zero collision risk with proper UUID implementation
- Sortable UUIDs (v7) for better database query performance
- Complete privacy—generated IDs never leave your browser
- Cross-platform compatibility on all devices
- Free and unlimited usage without registration
- Educational version comparison for informed choices
How to use the UUID Generator
- 01Enter or paste your input
- 02Adjust the options if you need to
- 03Run the tool
- 04Copy the result
Questions
- What is a UUID and what is it used for?
- A UUID (Universally Unique Identifier) is a 128-bit identifier designed to be unique across all devices and time without central coordination. UUIDs are used as database primary keys, session tokens, API resource IDs, file names, and anywhere you need guaranteed unique identifiers in distributed systems.
- What's the difference between UUID v1, v4, and v7?
- UUID v1 uses timestamp + MAC address (sequential but may expose machine identity). UUID v4 is fully random (most common, no embedded info). UUID v7 is time-ordered with random suffix (newest standard, best for databases as it's sortable by creation time).
- Can two UUIDs ever be the same?
- Theoretically possible but practically impossible. UUID v4 has 122 random bits, creating 5.3 × 10^36 possible values. You'd need to generate 1 billion UUIDs per second for 100 years to have a 50% chance of a single collision. In practice, treat them as guaranteed unique.
- Which UUID version should I use for database primary keys?
- UUID v7 is recommended for database primary keys because it's time-ordered, allowing efficient B-tree indexing and sequential inserts. UUID v4's randomness causes index fragmentation. If v7 isn't available, use v4 but consider the indexing impact on large tables.
- What's the difference between UUID and GUID?
- UUID (Universally Unique Identifier) and GUID (Globally Unique Identifier) refer to the same thing. 'GUID' is Microsoft's terminology, while 'UUID' is the standard term used in RFC 4122 and most programming languages. Both follow identical specifications.