Nothing leaves your computer, with one exception
Every calculation, drawing, label, sticker, PDF, picture and saved design is handled in your browser. WireAndWidgets has no accounts, no tracking, and no upload of your work. Files you open stay on your machine.
The one exception is the Report a bug or idea page. If you choose to send a message there, the message you type, the kind you pick and the tool you name are sent to our server and saved until we read them. That page explains exactly what is and is not kept, and it is the only place on this site that sends anything to a server. Every other page is set up so the browser blocks it from contacting any server.
Where your work is saved
Tools that keep your work save it in this browser only. Clearing your browsing data erases it, so use each tool's Export button for a backup file and Import to restore it on any computer. Installing the app makes browsers far less likely to clear it.
Open-source parts
The PDF markup tool uses PDF.js (Apache License 2.0) to draw pages and pdf-lib (MIT License) to write the marked-up copy. Their license files ship with the site in the static/vendor folder.
About the results
Estimates only, and they may be wrong for your specific installation. Not engineering, legal, or code-compliance advice. Check every result against the code edition adopted in your area, the manufacturer's instructions, and your local inspector (AHJ) before you install anything.
Using the tools means agreeing to the Terms of Service, which you are asked to accept once on each device.