UUID Generator
Generate random version 4 UUIDs (Universally Unique Identifiers) online. All UUIDs are generated client-side using the Web Crypto API.
What is a UUID?
A UUID (Universally Unique Identifier) is a 128-bit identifier standardized by RFC 4122. Version 4 UUIDs are randomly generated, making collisions practically impossible. They are widely used as primary keys in databases, session IDs, and distributed systems.
Related Tools
If you've ever needed a unique identifier for a database row, a test fixture, or a distributed system, you've probably reached for a UUID. A UUID (Universally Unique Identifier) is a 128-bit label that's practically guaranteed to be unique across space and time. Version 4 UUIDs — the kind this tool generates — use cryptographically secure random numbers under the hood. They're the go-to choice when you need IDs that don't depend on a central authority or database sequence. Most languages and frameworks support them natively — Python's uuid module, Java's java.util.UUID, and JavaScript's crypto.randomUUID() all do the job. This tool lets you generate them in bulk without writing a single line of code.
How to Use the UUID Generator
Choose the UUID Version
Select UUID v4 (random, most common) or another version from the options. v4 is recommended for most use cases.
Generate UUIDs
Click Generate to create a new UUID. You can generate in bulk — set the count to get multiple UUIDs at once.
Copy and Use
Click Copy to grab the UUID. Use it as a unique identifier in your database, API, or application.
Example UUIDs
UUID v4 (Random)
Format:
xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxxSample generated UUIDs:
550e8400-e29b-41d4-a716-446655440000
f47ac10b-58cc-4372-a567-0e02b2c3d479
3b9cde4e-2d5f-4c7b-a1e6-8f9c0d3b2a1fFrequently Asked Questions
What is a v4 UUID and how is it generated?
A v4 UUID is a 128-bit identifier where 122 bits are randomly generated and 6 bits indicate the version (4) and variant. This tool uses the browser's crypto.getRandomValues() for cryptographically secure randomness, following RFC 4122.
Can two UUIDs ever be the same?
Technically yes, but the probability is astronomically low. With 122 random bits, you'd need to generate around 2.71 quintillion UUIDs before a 50% collision chance. For all practical purposes, v4 UUIDs are unique. The UUID Wikipedia article has a detailed breakdown of the collision math if you want to go deeper.
Is it safe to use UUIDs as database primary keys?
Yes, and it's a common pattern — especially in distributed systems where auto-incrementing integers don't work well. The main trade-off is that UUIDs are larger (16 bytes vs 4-8 bytes for integers) and can hurt index performance in some databases. PostgreSQL has a native UUID type that stores them efficiently.
Are my generated UUIDs stored anywhere?
No. Everything runs in your browser using JavaScript. No UUIDs are sent to any server, logged, or stored. You can verify this by checking the Network tab in your browser's developer tools.