The shop has no sign. Or rather, the sign is obscured by some kind of bunting. The glass doors are papered over. You gotta know what's back there, like a speakeasy.

Venturing to open the door, I find I still can't get inside. Between me and a cramped 180 square feet or so of convenience store-like shelves—yogurts, bags of exotically-flavored freeze-dried peas, refrigerators full of juice, and pre-packaged sandwiches—is a turnstile. It is a shop. I will shop. There's a reader on the right. There's an app.

This is San Francisco, 2018. There is always an app.

Get the app and give it a credit card—just like Uber and Amazon trained us—and the app will spit back a QR code. Krishna Motukuri, the guy running the show, calls that code up on his phone and flips it over for the scanner; the turnstile's waist-high doors fold back. I saunter through. I'm in! I am shopping. I am free to pick whatever I want off the shelves. When I'm done, I get scanned back out. I have shopped.

Depending on how you count such things, the Zippin store and an Amazon store in Seattle are the only cashier-free stores in America.

But it's, like, future shopping. Because: No cashiers. No checkout lines. My purchase—well, Motukuri's, really—is a matter between me, my credit card company, and the store's tech. It's running off a system called Zippin, made by a company of the same name. The experience has been available to friends and other folks in the same building where this pop-up is housed, but it's now debuting a bit more widely. Depending on how you count such things, the Zippin store and an Amazon store in Seattle are the only cashier-free stores1 in America.

Video by Zippin

The Zippin store is set-up in a sort of lobby; up a short flight of steps, the space extends backward another 50 feet or so, and the company has set up second-hand conference tables, chairs, laptops. Shelves and drawers along one wall are artifacts of the room's previous life as a hair salon. If all goes as planned, the store will eventually expand back here, too. But that's not the point. "This is just purely to prove the concept," Motukuri says. "This technology can be applied in any retail store."

Zippin, he says, is "a software play." Software-as-a-service. All the hardware is commodity—the turnstile, the weight sensors in the shelves, the cameras in the ceiling that link your image to your unique QR code. It's up to the computers to match all that together and charge your card when you leave. (The computer puts a green square around your image from above; there's nothing biometric about it, unless someone figures out how to characterize individual differences in male pattern baldness.)

But...Amazon, though? That company's sans-checkout store in Seattle is the 500-pound gorilla riding the elephant in the room, isn't it?