LeanDevKit

Free developer tools that run entirely in your browser. Draw architecture diagrams and flowcharts; format, validate, compare and convert JSON, YAML, TOML, CSV, XML, SQL and Protobuf text; decode Base64, URLs and JWTs; and generate UUIDs, passwords, secret keys and hashes. No account, and your documents never leave your computer.

Private by design

Every tool runs on your device. What you type, paste or open is processed in the browser and saved in the browser's own storage, so your documents never leave your device.

Your work is saved as you go, and stays in sync between the browser tabs you have open.

With your permission, we count anonymous visits with Google Analytics to learn which tools are used. What you type is never sent. See Privacy.

Questions

Is LeanDevKit free?

Yes. There is no account to create and nothing to pay.

Where is my work stored?

In your browser, on your computer. Clearing this site's data in the browser removes it, so download anything you want to keep as a file.

Does it work on Mac, Windows and Linux?

Yes, in any modern browser. Keyboard shortcuts follow your system: ⌘ on a Mac, Ctrl elsewhere.