UUID Generator
Generate random UUIDs (v4) online. Free UUID generator — create one or bulk generate unique identifiers instantly.
Three steps to get started
Choose how many
Use the count selector to choose how many UUIDs you want — from 1 up to 100.
Click Generate
Click "Generate UUIDs" to instantly create cryptographically random UUID v4 identifiers.
Copy all
Click "Copy All" to copy all generated UUIDs to your clipboard, one per line.
UUID v4 generation explained
UUID (Universally Unique Identifier) is a standardized 128-bit identifier defined in RFC 4122. Its canonical string form looks like this: 550e8400-e29b-41d4-a716-446655440000
Version 4 UUIDs are generated using random or pseudo-random numbers. This tool uses the browser's crypto.randomUUID() API, which generates cryptographically secure random values. The result is a UUID where every bit (except the 6 version and variant bits) is randomly generated.
Common use cases for UUIDs:
- Database primary keys: Generate IDs on the client before inserting, enabling optimistic UI
- Distributed systems: Multiple services can generate IDs independently without coordination
- File names: Prevent filename collisions for uploaded files
- Session tokens: Unique, unpredictable session identifiers
- Idempotency keys: Deduplicate API requests safely
The uppercase toggle lets you switch between lowercase (the canonical format per RFC 4122) and uppercase, which some legacy systems require. Both formats represent the same UUID value.
All UUIDs are generated locally in your browser — no server requests, no logging, no limits. Generate as many as you need.