Privacy

MarketFees has no accounts, no sign-up and no database. Every calculation runs in your browser.

What is stored, and where

So you don’t have to retype a sale, each calculator saves its last inputs in your browser’s localStorage under keys starting with mf:. They never leave your device and we cannot see them.

Clear my saved inputs

The listing advisor

Only when you press “Get a recommendation”, the item description you typed and the fee numbers on screen are sent to our server and passed to an AI model through Vercel AI Gateway to write the answer. We don’t store the text. Your IP address is held in memory for a few minutes to limit abuse, then discarded.

Analytics

We use Ahrefs Web Analytics, which counts page views without cookies and without building a profile of you.

Accuracy

Fee rates are the published US seller fees as checked in September 2026. Platforms change them; confirm on the platform’s own fee page before relying on a figure for an expensive decision.