UUID Generator

Generate random v4 UUIDs with customizable formatting options

Count: Uppercase No Dashes

v4 Uppercase No Dashes

Click Generate to create UUIDs

About UUID Generator

The UUID Generator creates universally unique identifiers (UUIDs/GUIDs) instantly in your browser. UUIDs are 128-bit identifiers guaranteed to be unique across space and time, commonly used as primary keys, session tokens, correlation IDs, file names, and resource identifiers in distributed systems, microservices, and modern application architectures.

What Is a UUID?

A UUID (Universally Unique Identifier) is a 128-bit number represented as 32 hexadecimal digits in the format xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx. The UUID specification (RFC 4122) defines several versions: Version 1 uses timestamp and MAC address, Version 3/5 use namespace-based hashing, and Version 4 (used by this tool) generates 122 random bits using cryptographic randomness. With over 5.3 × 10³⁶ possible values, the probability of generating two identical UUIDs is essentially zero.

Key Features

UUID v4 generation — creates random UUIDs using the browser's cryptographically secure crypto.getRandomValues() API.
Bulk generation — generate dozens or hundreds of UUIDs at once for database seeding, batch operations, or test data creation.
One-click copy — copy individual UUIDs or all generated UUIDs to your clipboard instantly.
Standard format — outputs UUIDs in the standard 8-4-4-4-12 hexadecimal format (e.g., 550e8400-e29b-41d4-a716-446655440000).
Instant generation — UUIDs are generated in milliseconds, even in bulk, with no server dependency.
Privacy — all generation happens in your browser. No UUIDs are logged, stored, or transmitted.

How to Generate UUIDs

Set quantity — enter the number of UUIDs you want to generate (1 for single use, higher for bulk).
Generate — click Generate to create the UUIDs instantly.
Copy — click Copy next to any individual UUID, or copy all UUIDs at once.
Use — paste the UUIDs into your database schema, code, configuration files, or test data.

UUID vs. Auto-Increment IDs

Traditional auto-incrementing integer IDs (1, 2, 3...) work well for single-database applications. However, in distributed systems with multiple databases, microservices, or offline-capable apps, auto-increment IDs cause conflicts. UUIDs solve this by being globally unique without coordination between systems. They also prevent enumeration attacks (guessing other users' IDs by incrementing) and don't reveal record counts or creation order. The trade-off is larger storage size (16 bytes vs. 4-8 bytes) and less efficient database indexing.

Real-World Use Cases

Generating primary keys for database records in SQL (PostgreSQL, MySQL) or NoSQL (MongoDB, DynamoDB) databases.
Creating unique session identifiers, correlation IDs, or request trace IDs for distributed systems and microservices.
Generating unique file names, S3 object keys, or blob storage identifiers to prevent naming collisions.
Creating test data with unique identifiers for integration testing, load testing, and database seeding.
Assigning unique identifiers to IoT devices, API keys, or external-facing resource URLs.

Frequently Asked Questions

What is the difference between UUID and GUID?

UUID (Universally Unique Identifier) and GUID (Globally Unique Identifier) are the same thing. UUID is the standard term (RFC 4122), while GUID is the name used primarily in Microsoft/.NET ecosystems.

Are UUIDs truly unique?

UUID v4 generates 122 random bits, giving over 5.3 × 10³⁶ possible values. The probability of generating a duplicate is astronomically low — you'd need to generate 1 billion UUIDs per second for 85 years to have a 50% chance of one collision.

Can I use UUIDs as database primary keys?

Yes. UUIDs are widely used as primary keys, especially in distributed databases and microservice architectures where auto-incrementing integers would cause conflicts across nodes.

Are UUIDs sortable?

UUID v4 is randomly generated and not time-sortable. If you need time-sortable unique IDs, consider ULID or UUID v7 (draft specification) which encode timestamp information.

What UUID version does this tool generate?

This tool generates UUID v4 (random) identifiers using the browser's cryptographically secure random number generator. Version 4 is the most commonly used UUID version.