Seattle, Washington - Amazon is deploying its Just Walk Out shopping technology in the space of a full-fledged supermarket for the first time. The new grocery store in Seattle unveiled on Tuesday is just over 25,000 square feet.

The first stores featuring Amazon Go technology initially had an area of just over 1,200 square feet. Then, at the beginning of last year, Amazon opened its first Amazon Fresh branded store, which was about half the size of an average supermarket at about 10,000 square feet.

Now Amazon has determined that the concept is working well enough to warrant opening a store big enough to compete with rivals like Walmart and Target, at least as far as grocery products. The latest location is the fourteenth under the Amazon Fresh brand and utilizes the Just Walk Out concept.

In Amazon stores, customers simply take items off the shelf and leave the store. Cameras and other sensors, such as pressure sensors built into the shelves, register who has taken which goods, and the price is debited via the app after they leave the store.

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In years of developing the technology, Amazon has found it challenging to work with larger numbers of customers, according to The New York Times.

There are currently 29 Amazon Go stores around the world, 14 Amazon Fresh stores, and hundreds of subsidiaries like Whole Foods, book stores, and even a hair salon in London.

Amazon has also been offering the technology to other retailers since last year. In March, Amazon opened the first store of this kind in Europe in London. It runs under the Amazon Fresh brand, just like the new larger store in Seattle.