What is a UUID v4?
A UUID (Universally Unique Identifier) version 4 is a 128-bit identifier generated using cryptographically strong pseudo-random numbers. Unlike sequential database IDs (such as auto-incrementing integers), UUIDs can be generated distributedly across multiple systems and servers without risking ID collisions or requiring centralized coordination.
Standard UUID Format and Structure
A standard canonical UUID representation consists of 32 hexadecimal digits displayed in five hyphen-separated groups:
xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxxIn a version 4 UUID, the 13th hexadecimal character indicates the version (which is fixed to 4), while the 17th character indicates the variant (usually conforming to RFC 4122 / RFC 9562, where y is 8, 9, a, or b).
How to Use This UUID Generator
- Quantity: Choose how many UUIDs you need to generate at once (from 1 up to 100).
- Case selection: Toggle uppercase or lowercase depending on your language or database conventions.
- Instant generation: Click "Generate UUIDs" to generate a fresh batch using your browser's cryptographically secure pseudo-random number generator.
- Copy and Export: Click the copy button to copy all identifiers to your clipboard for use in database seeds, mock data, or test suites.
Security and Privacy Guarantee
All identifiers generated on this page are produced entirely on your device via crypto.randomUUID(). No requests are transmitted over the network, ensuring that newly generated keys, tokens, or session IDs remain completely confidential.