No account, no sign-up, no email field anywhere on the site.
Your league settings are remembered in your own browser. The calculator runs entirely there — no trade is ever posted to a server.
The trade you build lives in the page URL, which is why a link reproduces it exactly.
Share cards are drawn on your device. The image is never uploaded.
Analytics do receive your league settings. Changing one sends its name and value. Each settled result sends the verdict, which side it favours, all five settings, how many assets are on each side, and which of the four terms decided it. That is how we learn which formats to build for.
Adding or removing an asset sends its position — QB, RB, WR, TE or pick — never the player. Sharing sends how you shared and whether it worked.
A search that finds nothing sends how many characters you typed, never the text. It tells us a player may be missing without telling us who you were looking for.
The page address sent to analytics is stripped of its query string, so the trade in your URL is not included. A scrubber also drops any value matching a player or pick name before anything is sent — a belt as well as braces.
That stripping is enforced in the page itself. One analytics setting also has to be switched off in the provider’s console, which we cannot verify from here; it is written down in the project README so it is checkable rather than assumed.