What is UUID v4 Generator?
UUID v4 Generator uses the browser's cryptographic random source to create standard random identifiers with correct version and variant bits. It is useful for database records, test data, and offline client objects. A UUID is an identifier rather than a permission boundary and should not be treated as a password or secret access token. Common workflows include the following. Generate record IDs for test fixtures. Assign temporary identifiers to offline-created client objects. Fill UUID v4 fields in example API requests. The page also documents input boundaries, output behavior, and practical cautions so you can review the result before putting it into an application, configuration, test, or production workflow.
When to use it
- Generate record IDs for test fixtures.
- Assign temporary identifiers to offline-created client objects.
- Fill UUID v4 fields in example API requests.
How to use it
- Enter a quantity from 1 to 100.
- Generate UUID v4 values with the browser cryptography API.
- Copy the newline-separated result.
- Load one of the realistic examples first to verify the selected options and processing direction before replacing it with your own data.
- Review the output, status message, and documented limits; copy, download, or continue only after the result matches your expectation.
Runnable examples
The “Example 1” and “Example 2” buttons load the matching inputs. They cover different structures, directions, or boundaries and can be run directly in the workspace.
Example 1
12Example 2
48Input rules
- The requested count must be an integer from 1 to 100.
- The browser must support crypto.getRandomValues.
- Do not use a UUID as an authorization credential or confidential value.
- Text input is counted before processing and is limited to 100 characters on this page; file modes apply the separate file limit shown in the workspace.
- Generation is limited to 100 UUIDs per action.
Output rules
- One lowercase UUID is produced per line.
- The version is 4 and the variant follows RFC 4122.
- Fresh random bytes are used each time, so results are not sequential.
- Output reflects only the current input, direction, and options; rerun after changing a mode or value instead of treating an earlier result as current.
- UUIDs are identifiers, not secrets or access tokens.
Limitations and cautions
- Generation is limited to 100 UUIDs per action.
- UUIDs are identifiers, not secrets or access tokens.
- The tool produces UUID v4 only.
How your data is handled
Random bytes and UUID formatting stay in the browser, and generated values are not sent to a server.