Online retail giant Amazon has launched a service that lets its delivery staff drop off packages inside a customer's home while they are out.

Amazon Key combines an app, a smart lock and the new Amazon Cloud Cam – an indoor security camera – to provide in-home delivery without the need for physical keys or access codes.

When a driver requests access to a customer's home, Amazon ensures they are at the right address at the right time through an "encrypted authentication process".

Once verified, the door is automatically unlocked and the Cloud Cam records the drop-off. Users can watch this live or review a recording later, and receive regular notifications about the delivery status all through the app.

The service will be available for subscribers to the company's Prime service, initially in 37 US cities, from 8 November 2017.

"Amazon Key gives customers peace of mind knowing their orders have been safely delivered to their homes and are waiting for them when they walk through their doors," said Amazon vice president of delivery technology Peter Larsen. "Now, Prime members can select in-home delivery and conveniently see their packages being delivered right from their mobile phones."

The set-up also allows users to let friends, family and other visitors – cleaners, pet sitters, dog walkers etc – into their homes when they are not there.

An Amazon Key In-Home Kit includes an Amazon Cloud Cam and a compatible smart lock, by manufacturers Yale and Kwikset, and starts at $249.99. Users can set up the system themselves, or opt for free professional installation.

The service will work with same-day, one-day, two-day and standard shipping by selecting "in-home" when purchasing on Amazon.com, at no extra delivery cost to Prime members.

Amazon's vision for the future of delivery also includes drop-offs by drone, which the company has been testing since 2013.