The smart doorbell market used to be just for tech enthusiasts and early adopters, but now these door cameras are becoming a familiar sight when you walk around any neighbourhood.
Our first full test of smart doorbells has revealed three Best Buys, along with some decent models that are worth considering for less than £100. It also uncovers the models you should avoid.
Alongside reviews of the doorbells themselves, we've got advice covering everything you need to know when buying one: from installation and security against hackers, to additional subscription services.
Smart doorbells are discreet, internet-connected cameras that are installed on or beside your front door (or any external door).
They can alert you if someone arrives by sending a notification to your phone; you can see a video of who's at the door and even talk to them with two-way audio.
Amazon's Ring dominates the market, but it has competition from Google's Nest Hello.
Ring's biggest competitor is the Nest Hello, from the Google-owned smart home brand. Get the lowdown on the Nest Hello below.
Whether you choose Ring or Nest, you'll need to factor in the likely need to sign up to a subscription service to get the most out of your smart doorbell.
While you can watch live video and receive notifications out of the box, you'll have to sign up to Ring Protect or Nest Aware to record video clips over a month in case you need them.
The Nest Hello is a stylish, smart video doorbell that will blend in discreetly with most homes. It has a 1080p HD camera with infrared night vision, meaning it can also show what's going on even in the pitch black of night.
The Hello will require a wired installation (see more on that below), but once it's up and running you won't need to worry about keeping the battery charged, as with the two Ring doorbells featured here.
Although you can store three hours of video to access online free of charge, most people will feel the need to sign up to Nest Aware (£5 a month/£50 a year) for up to 30 days of storage. Other useful features, such as improved motion alerts, also require Nest Aware.
The Ring Video Doorbell (2nd gen) is the cheapest doorbell in Amazon's Ring range, and is a popular choice. It has all the core functions of more expensive Ring doorbells - 1080p video, night vision, motion detection - but costs less than £100.
Unlike the Nest Hello, not all Ring doorbells offer free video recording as standard, so you'll need to sign up to Ring Protect unless you're happy with live monitoring only.
With Protect Basic, you get 30 days of video storage for a single Ring device for £2.50 a month, or £24.99 a year. Upgrade to Protect Plus if you have more than one Ring device, such as a doorbell and a wireless camera. You get a 30-day trial to try the service out.
This Ring model could be an excellent choice if you already have a peephole in your front door. To install it, you unscrew the peephole with the supplied tools, and then thread the camera unit through the existing hole. You fix it on the inside of the door by connecting it to the battery power unit.
The Door View Cam has the same 1080p HD video and motion notifications of the other Ring cameras, but you can also look down the peephole as you would normally to see who's at the door. And unlike the Ring Video Doorbell (2nd gen), its battery is removable, so you won't need to detach the entire doorbell when it needs to be charged.
Have another model in mind? We've run a bunch through our tough lab tests, so check our reviews to see how they fared.
All doorbells will need to be installed either on your door, or next to it. That means when buying a smart doorbell, you'll need to consider the type of power it uses, as this will factor into the installation.
It's possible to install a battery-powered doorbell yourself if you're confident enough with DIY. But a hard-wired model will most likely require a professional installation, and this will be an additional cost to consider.
Some battery-powered doorbells, such as the Ring Door View Cam, have removable batteries, so it's advisable to have a fully charged spare battery ready to go if you need it.
Others, such as the Ring Doorbell (2nd gen), have built-in batteries, so you'll need to remove the entire doorbell to charge it.
You can connect a battery doorbell to the mains so that it's 'trickle charged' to keep the battery topped up. Again, we'd advise you get a professional in instead of attempting this yourself.
We put smart doorbells and their associated apps through a full security assessment, including whether they use strong passwords, encrypt your private information and protect you from basic hacking attacks.
We also check whether a criminal could easily detach the doorbell from your home and steal it in order to resell the doorbell, or just stop it working while they attempt to burgle your property.
Outside of the bigger and more established brands, there's a huge number of smart doorbells available from little-known brands (or those with no apparent brand name at all) on online marketplaces, often at tantalisingly low prices.
We would urge you to be cautious when considering a smart doorbell from a little-known brand. You might find that it's hackers who come calling to your home.