These shipments were made in accordance with a bilateral trade agreement between the United States and China that originated in 2010, meant to address the rising tide of cross-border e-commerce. Items up to 4.4 pounds — more than the weight of, for example, a violin and bow — can be shipped as ePackets, at extremely low rates with tracking numbers and delivery confirmation. Tracking is crucial for foreign sellers that are up against consumer skepticism and comparatively slow shipping times. The deal seems to have worked: ePacket’s usage has ballooned in recent years.

This obscure trade deal has become the quiet conduit for an explosion in a new and underexamined American consumer behavior: buying things directly from their countries of manufacture. (Similar agreements also exist with Hong Kong, Singapore and South Korea.) This, obviously, presents a problem for the stores and retailers accustomed to serving as importers themselves. Brick-and-mortar retailers are already experiencing a grim 2017, shedding tens of thousands of jobs a month under pressure from e-commerce. Cross-border purchases compound the issue: Because of ePacket, and the decades-old international postal agreements that serve as its foundation, lightweight product shipments from China are heavily subsidized by the U.S.P.S. “It’s providing an artificially low rate,” says Jim Campbell, a consultant and lawyer specializing in international postal law. “It’s redistributing wealth, and the winners are essentially the big exporters.” Accordingly, these agreements have drawn intense criticism from American retailers large and small. In 2015, an Amazon representative testified in front of Congress about what he called a “completely unnecessary and illogical” system.

It’s tempting — and not entirely unfair — to see this surge in American cross-border shopping as nothing more than a strange side effect of international postal policy. But that would be too tidy. Wish certainly illuminates the peculiarities of international shipping, but it casts a much brighter light on the state of globalized manufacturing and commerce. In fact, it offers a somewhat convincing vision of what they might become in the near future.

The Walmart shopping experience is largely opaque with respect to the chain’s dependence on imports. A product’s country of origin is relegated to labels or printed on mandatory stickers, subordinate to a curated and thoroughly American shopping experience. Wish wastes no such effort on concealing its international character. Its product selection feels like a churning, infinite cascade; its lack of any sort of organizing principle is part of the reason it’s so hard to stop scrolling. More recently, I ordered a smartwatch for the cost of a combo meal. The seller has shipped more than 13,000 units through Wish, and the watch has been reviewed more than 2,000 times. A single day produced ratings written in English, Spanish, Danish, Cebuano, German, French and Romanian.