UUID Generator – Create Random v4 UUIDs Free
Generate UUIDs (v4) for your applications.
How to use this uuid generator
- Drag the slider to choose how many UUIDs you want to generate (from 1 to 100)
- Click the "Generate UUID(s)" button to create that many version 4 UUIDs
- Review the generated UUIDs listed in the output textarea, one per line
- Click the copy button to copy all generated UUIDs to your clipboard at once
- Adjust the slider and click generate again anytime to produce a fresh batch
Frequently Asked Questions
What is a UUID?
UUID (Universally Unique Identifier) is a 128-bit identifier used to uniquely identify information. Version 4 UUIDs are randomly generated.
Are UUIDs really unique?
While theoretically possible, the probability of generating duplicate UUIDs is extremely low (about 1 in 5.3 × 10^36). For practical purposes, they are considered unique.
What version of UUID is generated?
This tool generates UUID version 4, which uses random numbers. It's the most commonly used version for generating unique identifiers.
Related Tools
A UUID generator helps developers, database designers, and QA engineers quickly produce unique identifiers for records, test fixtures, API keys, or temporary IDs without writing any code. This tool is useful when seeding a database with sample data, generating placeholder primary keys during prototyping, creating unique session or request identifiers for testing, or filling in IDs for mock objects in unit tests. Instead of reaching for a script or library, you can generate one or many UUIDs directly in the browser and copy them wherever they're needed. The tool lets you choose how many identifiers to generate at once, which is handy when you need a batch of test IDs rather than a single value.
What is uuid generator?
This UUID generator produces version 4 UUIDs, the random-based variant of the UUID standard. Each UUID is built from a 36-character template of hexadecimal digits and hyphens, where the random positions are filled using JavaScript's Math.random(), and two fixed positions are set according to the UUID v4 specification: the version nibble is always set to 4, and the variant nibble is constrained to one of four values (8, 9, a, or b) as required by RFC 4122. This produces identifiers that follow the standard UUID v4 format and are extremely unlikely to collide with each other in practice. You can generate up to 100 UUIDs at once by adjusting a slider before clicking generate.
Common use cases
- Generating primary key values while prototyping a database schema before wiring up real ID generation
- Creating batches of unique test fixture IDs for unit tests or seed scripts
- Producing temporary session, request, or correlation IDs while debugging distributed systems
- Filling placeholder unique identifiers into mock API responses or sample JSON payloads
- Generating a quick unique filename or resource identifier when manually testing an upload flow
- Creating unique keys for React lists or other UI components during development
Limitations and common mistakes
- UUIDs are generated using JavaScript's Math.random(), which is not cryptographically secure — do not use these values for security tokens, password reset links, or anything requiring unpredictability
- Only UUID version 4 (random) is supported; this tool cannot generate version 1 (time-based), version 5 (name-based), or other UUID variants
- You can generate at most 100 UUIDs per click; larger batches require generating multiple times and combining the results
- Uniqueness is probabilistic, not guaranteed; while collisions are astronomically unlikely, this tool has no mechanism to check generated UUIDs against existing ones in your system