Proxy shopping is a purchase-and-logistics workflow, not just a translated catalog
The service adds value when it keeps the Japanese source visible while solving local checkout, domestic receipt and international shipment. A useful page should let a buyer move from search or pasted URL to an order without losing seller context. It should also expose which cost is known now and which will only become final at the warehouse.
A proxy should preserve the marketplace rather than flatten it
Mercari seller evidence, Yahoo auction rules and an Amazon seller offer are different kinds of source information. A useful proxy interface carries those distinctions into the order instead of converting everything into a generic product card that hides where the information came from.
Use one cost ledger across the whole order
Track item price, Japan domestic delivery, service/payment charges, warehouse work, international freight and import amounts in separate rows. The buyer can then compare marketplaces and proxy services without double-counting one layer or forgetting another.
What the interface should make explicit
For shopping, the service should show which facts come from the Japanese source, which amounts are estimates, which stage is waiting on a seller or warehouse, and what action the buyer can still change. On Japan Proxy Shopping, that separation tells the buyer whether the unresolved issue is source evidence, money, timing or the physical shipment, instead of hiding all four behind one generic status.
A unified search still needs source boundaries
Showing Mercari, Yahoo Auctions and retail inventory in one interface is useful only if the result card also tells the buyer what kind of transaction follows. Fixed-price seller listings, timed auctions and store catalog offers carry different evidence and availability rules; unified discovery should not pretend they are one marketplace.
One cart can still contain different states
A store item can be purchased, an auction item can still be bidding, and a Mercari order can be waiting for seller dispatch at the same time. The cart/account model should preserve those states separately while allowing later warehouse consolidation when the physical items actually arrive.