Amazon is planning to deliver packages inside your home

Amazon has plans to drop off packages directly into shoppers' homes.

On Wednesday, the world's largest online retailer announced Amazon Key — a lock and camera system that users control remotely to let couriers deliver goods right inside their houses.

The move, in the works for more than a year, may help Amazon capture sales from shoppers who could not make it home to receive an order in person, and did not want the package stolen from their doorstep. It also signals Amazon's ambitions in the growing market for home security devices, where Google parent company Alphabet's Nest Labs competes.

How does it work? First, the customer fits a "Cloud Cam" camera inside their hall and a compatible smart lock on their door. Then when an Amazon courier arrives, they are able to unlock the door and drop the package off inside. The camera, meanwhile, records the delivery to make sure it all goes as it should (making sure the courier doesn't wander off inside the customer's home, for example).

Alternatively, it can be used to let in professional services like cleaners, and can create temporary passcodes for friends.

'This is a core part of the Amazon shopping experience'

"This is not an experiment for us," said Peter Larsen, Amazon vice president of delivery technology, in an interview with news wire Reuters. "This is a core part of the Amazon shopping experience from this point forward."

It's only available to Amazon Prime members in certain cities in the US so far, who can pay $249.99 (£189) and up for a cloud-controlled camera and lock that the company offers to install. Couriers are told to ring a doorbell or knock when they arrive at someone's house. If no one greets them, they press 'unlock' in a mobile app, and Amazon checks its systems in an instant to make sure the right associate and package are present.

The camera then streams video to the customer who remotely can watch the in-home delivery take place. The delivery associate cannot proceed with other trips until the home is again locked.

There are obvious security and privacy concerns

It is unclear if such protections will persuade customers that the service is safe to use. After all, there are obvious security and privacy concerns: Do you really want to grant Amazon the power to unlock your front door at any time? What happens if the lock fails due to a technical glitch? Are you comfortable with couriers entering your home without you there?

Larsen said theft was "not something that happens in practice," based on early tests of the Amazon Key program.

He added that if a problem arises, "You can call customer service, file a claim and Amazon will work with you to make sure it's right," reimbursing customers in some cases.

Wal-Mart, Amazon's biggest retail rival in the United States, has similar plans. It said last month it would test delivering grocery items "straight into your fridge" with August Home, a smart lock business that Assa Abloy AB said it will acquire.

Amazon's new service goes live on November 8 in 37 U.S. locations, the company said. The "Cloud Cam" is also available by itself for purchase, it said.