BayScope

BayScope is a browser extension for Chrome and Firefox that shows eBay sellers real time analytics directly on the platform. You see price comparisons, market trends, competition analyses and an integrated fee calculator without leaving eBay.

The extension helps you set better prices, identify market opportunities and realistically estimate your profit margins. All data is calculated from publicly visible eBay information.

BayScope was built for eBay sellers who want to make data driven decisions and increase their revenue.

BayScope automatically detects whether you are visiting an eBay listing page, search results page or seller page and shows relevant analytics.

The price comparison shows you how your item compares to similar offers. You see average prices, price ranges and the optimal price positioning.

The fee calculator computes the actual eBay fees, shipping costs and your net margin for each listing. This way you know before listing whether an item is worth it.

The competition analysis shows you the most important competitors in your category with their sales numbers and ratings.

The price comparison analyzes not only the current price, but also shipping costs, item condition and listing type (auction vs. buy it now). This gives you a realistic picture of the total price.

The competition analysis identifies the most active sellers in your category and shows you their strategies: price positioning, listing frequency, rating profile and shipping options.

BayScope stores analysis data locally in IndexedDB. This allows you to track price trends over time without data being sent to external servers.

BayScope is built with JavaScript in Manifest V3 format. The extension uses content scripts for integration into eBay pages and stores analysis data locally in IndexedDB.

There is no custom backend server. All calculations take place in the browser. Data is read from the publicly visible elements of the eBay page.

BayScope is useful for different types of eBay sellers.

If you sell used items, the price comparison helps you find the optimal price. You immediately see what similar items currently cost, what the price trend looks like and in which price range most sales take place.

For commercial sellers, the fee calculator computes the actual eBay fees including shipping costs and commissions. You know before listing whether an item is worth it and how high your net margin will be.

The market trend analysis is particularly helpful when you want to enter new product categories. You can see which categories are growing, how high the competition is and what prices the market accepts.

For collectors and hobby sellers, BayScope provides a quick overview of the current market value of their items.

BayScope works entirely locally. No data is sent to external servers. The extension only reads publicly visible eBay information. Your eBay login credentials are not read or stored.