Seen

Seen keeps track of which eBay listings you've already opened and marks them in search results, so you don't keep clicking into the same ones.

Open a listing and that's it. The next time it shows up in search, browse, or home page results, it's dimmed and stamped with an amber "SEEN" sticker. If you can already tell from the thumbnail that you're not interested, hover over the result and click the "SEEN?" chip to mark it without opening it. Clicking a sticker unmarks it.

A toggle in the corner of the page hides seen listings from results entirely and shows how many are on the current page.

Marks sync between your computers through your Chrome profile. The extension keeps about six months of history (up to around 4,800 listings) and clears older marks on its own. If you want to clear things out sooner, click the toolbar icon and purge everything older than 1, 2, 3, or 6 months.

There are no network requests and no server behind this extension. It stores a list of eBay item numbers in your own Chrome sync storage, nothing more. It runs on eBay search, browse, home, and item pages only, never on cart, checkout, or messages.

Works on ebay.com.