Amazon is currently striving to permeate into every aspect of a house’s life, in an attempt to make life a bit easier for its users. Alexa, the basis of this endeavor, already connects to a number of gadgets and home appliances, and these are constantly expanding. Now, Amazon has purchased a startup with its own smart doorbell: Ring.

GeekWire broke the news of the purchase last Tuesday, and Reuters later confirmed that, while the sum was not yet specified, it was believed to be over $1 billion. That amount would turn it into one of the biggest Amazon purchases to date, comparable to last year’s Whole Foods Market acquisition.

Ring is focused on home security products that mix motion-based cameras with sounds. The most famous is Ring Video Doorbell, a smart doorbell that allows homeowners to remotely operate their doors. The product gained notoriety after company founder Jamie Siminoff went on Shark Tank to promote it in 2013. It was later crowdfunded and made hundreds of millions of dollars, thanks to big investors like Virgin Group’s Richard Branson and Goldman Sachs.

The purchase doesn’t necessarily come as a massive surprise, as Ring and Amazon already have a history together. The startup was a recipient of Amazon’s Alexa Fund, which gives funding to voice-based technology.

The purchase is an interesting move from Amazon, which seems to be focusing more and more on Alexa as a whole, and particularly on home security tech. Last year, the company acquired Blink Home, which produces battery-powered security cameras. It’s expected to eventually work with Amazon Key, the Prime service that allows users to monitor who comes and goes into their homes. Ring would most likely be connected with Key eventually, too.

Like it’s happened with other startup acquisitions, it’s expected that Ring continues to function separately from Amazon.