Generate UUIDs
A version 4 UUID is 122 bits of randomness formatted into the familiar 36-character shape. These are generated with the browser's cryptographic random source (crypto.getRandomValues), not Math.random, so they are suitable anywhere a v4 UUID is. Set How many to get a batch, one per line.
Example
Every output is different by design. The third group always starts with 4 (the version) and the fourth starts with 8, 9, a, or b (the variant).
Input and output
This tool takes no input. Output is one UUID per line, lowercase, hyphenated. The count option accepts 1 to 1000.
Collision risk at this scale is not a practical concern: the randomness per UUID is 122 bits. If you need identifiers that sort by creation time, the Toolbox also generates ULIDs.
Privacy
This tool runs entirely in your browser. The input is never uploaded, logged, or stored; close the tab and it is gone. The one deliberate exception in the whole Toolbox is the explicit Save as new paste button on the output, which does exactly what it says and nothing before you press it.
Generation is local. No server ever knows which UUIDs you generated, which matters if they become primary keys in your system.
Common uses
- Filling test fixtures and seed data with realistic identifiers
- Generating a correlation id to trace a request through logs by hand
- Creating a one-off unique name for a resource or feature flag
- Producing a batch of ids for a spreadsheet or CSV import
Need to share the result?
Run the tool, then use Save as new paste on the output to get a link you can send. The paste is unlisted, expires in a week, and the recipient needs no account. Or start from a blank paste if you already have the text.
Related tools
More tool pages: Format and validate JSON, Decode Base64 to text, Decode a JWT, Convert a Unix timestamp to a date, Convert CSV to JSON. Everything else lives in the full Toolbox, which also chains tools into workflows.