UUID Generator
Generate cryptographically secure UUIDs (Universally Unique Identifiers) instantly with our online tool. Our generator creates RFC 4122 compliant identifiers for your projects.
UUID Settings
Choose between random (v4) or timestamp-based (v1) UUIDs
Multiple Versions
Support for UUID v1 (timestamp-based) and v4 (random) with RFC 4122 compliance for all your identifier needs.
Bulk Generation
Generate up to 50 UUIDs at once with customizable formats, perfect for testing and bulk operations.
Secure & Reliable
Cryptographically secure generation with guaranteed uniqueness. Copy individual UUIDs or export all at once.
Tool Purpose & Audience
The UUID Generator creates Universally Unique Identifiers (UUIDs) — 128-bit identifiers formatted as 32 hexadecimal digits in the 8-4-4-4-12 pattern (e.g., 550e8400-e29b-41d4-a716-446655440000) — that are statistically guaranteed to be unique without requiring a central coordinator to manage ID assignment.
Backend developers, database administrators, API designers, and distributed system architects use UUID generators to create unique primary keys, session tokens, request IDs, correlation IDs, and idempotency keys — anywhere a globally-unique identifier is needed without querying a central sequence generator.
Real-World Use Cases
- Database primary keys: UUIDs as primary keys allow records to be created across multiple servers, services, or offline clients without ID conflicts — critical in microservices architectures where multiple services write to the same database.
- API request tracing: Assign a UUID to every incoming API request as a correlation ID — log it at every step of processing so you can trace the full journey of a request across multiple services in your logs (distributed tracing).
- File and asset naming: When users upload files, rename them with a UUID to avoid filename collisions, prevent path traversal attacks from predictable filenames, and ensure no two uploads overwrite each other regardless of the original filename.
- Idempotency keys for payment APIs: Payment APIs (Stripe, PayPal) accept an idempotency key — typically a UUID — so that if a request times out and is retried, the payment is only processed once. Generate a fresh UUID per payment attempt.
Practical Input → Output Examples
1. Standard UUID v4 (random)
Settings: Version 4, hyphenated format
Output: "f47ac10b-58cc-4372-a567-0e02b2c3d479"
UUID v4 uses random bytes for all 128 bits (with the version and variant bits fixed). It's the most widely used UUID format — no timestamp, no MAC address, purely random and privacy-preserving.
2. UUID without hyphens (compact)
Settings: Version 4, no hyphens
Output: "f47ac10b58cc4372a5670e02b2c3d479"
The compact form (32 hex characters, no hyphens) is used in some systems where hyphens aren't supported in IDs or where a shorter database column (CHAR(32) vs CHAR(36)) is preferred.
3. Bulk UUID generation
Settings: Generate 10 UUIDs at once
Output: 10 unique UUIDs, one per line
Bulk generation is useful for pre-generating UUIDs for batch database inserts, test fixtures, or seeding scripts — copy all 10 at once for immediate use.
Common Mistakes & Misunderstandings
UUID v1 exposes your MAC address: UUID version 1 is timestamp-based and includes the MAC address of the generating machine in the UUID itself. This exposes internal network identifiers and makes the UUID somewhat predictable (given knowledge of the timestamp and MAC). For privacy and security, use UUID v4 (random) instead of v1 in modern applications.
UUIDs are not sequentially ordered: Unlike auto-increment integer IDs (1, 2, 3...), UUID v4 values are random and have no natural sort order. Inserting UUIDs as primary keys in B-tree indexes (like MySQL's InnoDB) causes random index fragmentation and degrades insert performance at scale. Consider UUID v7 (sortable, time-based) or ULIDs for database primary keys where insert performance matters.
Collision risk is real but infinitesimally small: Two UUID v4 values could theoretically be identical — but the probability is about 1 in 5.3×10³⁶ for any two given UUIDs. For all practical purposes, UUIDs are unique. The "UUID collision" concern is a theoretical curiosity, not a real operational risk.
UUIDs should be stored as binary in databases: Storing UUIDs as VARCHAR(36) text takes more storage and is slower to index than storing as BINARY(16). Most databases have a native UUID or binary type — use it. MySQL and PostgreSQL both support efficient UUID storage natively.
What is a UUID and why should I use one?
A UUID (Universally Unique Identifier) is a 128-bit identifier that is guaranteed to be unique across time and space. UUIDs are essential for distributed systems, databases, and applications where you need unique identifiers without central coordination. They're widely used in software development, APIs, and database records.
What UUID versions are supported?
Our generator supports multiple UUID versions including Version 1 (timestamp-based), Version 4 (random), and Version 5 (namespace-based). Version 4 is the most commonly used as it provides strong randomness and doesn't reveal any information about the generating system.
Are the generated UUIDs cryptographically secure?
Yes, our UUID generator uses cryptographically secure random number generation to ensure that UUIDs cannot be predicted or reproduced. This makes them suitable for security-sensitive applications, session tokens, and unique identifiers in production systems.
Can I generate multiple UUIDs at once?
Absolutely! You can generate multiple UUIDs in a single operation, which is perfect for bulk operations, testing scenarios, or when you need multiple unique identifiers for your application. Each UUID is guaranteed to be unique.
What formats are available for UUID output?
The tool supports various UUID formats including standard hyphenated format (8-4-4-4-12), uppercase/lowercase variations, and compact format without hyphens. You can also copy individual UUIDs or export all generated UUIDs for use in your projects.