Kaufes lets people buy an item two ways: bid in an auction, or buy it now at a fixed price. Someone browsing needs to search for an item, understand what they're looking at, pick how they want to buy it, and see what it'll cost to ship — without the two buying paths feeling like two different apps.

I built the frontend for all of that, working with the backend, design, and Swiss Post's shipping team. That also covered payments and the checks that keep listings and sellers trustworthy.