Amazon has found a way to eliminate checkout lines, by getting rid of checkouts altogether.

After four years in development, the online retailer is nearly ready to launch its latest innovation, Amazon Go, a brick-and-mortar store that will allow Amazon shoppers to shop and exit the supermarket without stopping at the cashier. All they have to do is scan their phones at the entrance using the Amazon Go mobile app. Then, thanks to a combination of computer vision algorithms, sensors and AI, the technology will track only the products they pick up and add them to a virtual shopping cart in real time. Amazon seems confident the innovation will also be able to prevent shoplifting.

The first of these next-gen supermarkets will open to the public in Seattle early next year.

Here’s how it will work: