UUID Generator
Generate v4 UUIDs instantly for IDs, tokens, and test data.
Generate v4 UUIDs for IDs, fixtures, tokens, analytics events, and test data without leaving the browser.
What is this tool?
A UUID is a standardized identifier used to uniquely identify objects in software systems. Version 4 UUIDs are generated randomly and are commonly used for database rows, fixture data, temporary IDs, and distributed systems where uniqueness matters. They are widely used because they provide a reliable way to generate unique values without coordination between services.
Example
Example UUID
Valid v4 UUID
550e8400-e29b-41d4-a716-446655440000
Typical usage
Example in code
user_id = '550e8400-e29b-41d4-a716-446655440000'
Why use Cassidor?
- Generates values instantly for development and testing.
- Useful for mock data, fixtures, and temporary IDs.
- No account or setup required.
Frequently asked questions
What is a UUID v4?
It is a randomly generated UUID version 4 value, commonly used where uniqueness matters without centralized coordination.
Why use UUIDs instead of numeric IDs?
They are useful when you want an identifier that is unique across systems or when you need a less predictable value.
Can I generate many values at once?
Yes. The tool supports generating multiple UUIDs in one pass for fixtures and bulk test data.
Are UUIDs guaranteed unique?
They are designed to be highly unique in practice, though no system can guarantee absolute uniqueness without careful operational constraints.
Related tools
Format JSON instantly in your browser. Paste a payload, tidy the structure, and copy or download the result without affecting the data itself.
Encode text to Base64 or decode it back when you need to inspect API payloads, URLs, or encoded data quickly.
Test patterns against text to validate match logic, debug extraction rules, and quickly reason about regular expressions.