What this tool does
The UUID generator is useful for test data, object identifiers, API mocks, imports, and interface development.
How to use
- Enter the number of UUIDs you need.
- Choose the output format and press the generate button.
- Copy the finished values.
UUID v4 format
A UUID v4 is a 128-bit identifier usually written as five groups of hexadecimal characters separated by hyphens, such as 550e8400-e29b-41d4-a716-446655440000. In version 4, most bits are random while specific positions mark the UUID version and variant.
The format is convenient for test data, import spreadsheets, mock objects, temporary UI keys, and correlation IDs in logs. It travels well across languages and databases because it is just a predictable-length string.
Randomness and uniqueness
The generator uses the browser cryptographic API when available, which makes it suitable for practical development tasks. The chance of a random UUID v4 collision is extremely small for ordinary test and application volumes.
Still, UUIDs do not replace uniqueness rules. If an identifier is stored in a database, keep a unique index or application-side check so the system can handle rare collisions, duplicate imports, or manual mistakes.
Security and limits
A UUID is not a password, access token, or proof that someone may access a resource. It is fine as an identifier, but security should not rely only on the fact that the string is hard to guess.
Generation happens locally in the browser and does not need a server. You can create multiple values at once, choose an output format, and paste the result into tests, seed files, fixtures, or documentation.
When moving UUIDs between CSV, JSON, and databases, keep them as strings rather than numbers. That preserves hyphens, leading characters, and predictable comparisons.