UUID Generator Online
Generate random UUIDs (v4) instantly. Bulk generation, uppercase, and no-dash options available.
About This Tool
The UUID Generator creates cryptographically random version 4 UUIDs (Universally Unique Identifiers) following RFC 4122. UUIDs are 128-bit identifiers used as primary keys in databases, API resource IDs, session tokens, and anywhere you need globally unique values without central coordination.
Key Features
- Bulk Generation — Generate up to 100 UUIDs in a single click using the Count selector, ideal for database seeding and test data creation.
- Uppercase & No-Dash Options — Toggle uppercase output or strip dashes for UUID formats required by specific databases or APIs.
- Copy All at Once — The Copy All button copies every generated UUID to your clipboard as newline-separated values for batch use.
- Browser-Based Processing — All operations run locally in your browser. Your data never leaves your device.
- Free & No Signup — Use this tool as many times as you need without creating an account or paying anything.
Common Use Cases
- Generating unique primary keys for new database records in PostgreSQL, MySQL, or MongoDB
- Creating unique correlation IDs for distributed system requests and API call tracing
- Seeding development databases with realistic unique identifiers for testing
- Generating unique filenames for uploaded files to avoid name collisions in storage systems
- Creating idempotency keys for payment APIs and other sensitive transactional operations
How to Use
Select the number of UUIDs to generate from the Count dropdown, then optionally check Uppercase or No Dashes to customize the format. Click Generate to create fresh UUIDs. Click any individual UUID to select it, or use Copy All to copy the entire list to your clipboard.
Frequently Asked Questions
What is UUID v4 and how is it different from v1?
UUID v4 is fully random (except for a few version bits), providing strong unpredictability. UUID v1 uses a timestamp and MAC address, making it sequential but potentially exposing machine information. This tool generates v4 UUIDs.
Are UUIDs truly unique?
In practice, yes. The probability of two v4 UUIDs colliding is approximately 1 in 5.3 × 10³⁶. You would need to generate billions per second for decades to have even a small chance of a collision.
Can I use UUIDs as primary keys in SQL databases?
Yes. PostgreSQL, MySQL, and SQL Server all support UUID primary keys natively. They enable distributed ID generation without coordination, at the cost of slightly larger indexes compared to sequential integers.
What is a GUID? Is it the same as a UUID?
GUID (Globally Unique Identifier) is Microsoft's term for the same concept. GUIDs and UUIDs use the same 128-bit format and are fully interchangeable in practice.
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