Good quality surveillance systems and alarm systems are very simple to integrate into your home.
For retrofit applications, there are many great quality WiFi based cameras on the market. You can start by replacing your front doorbell with a video doorbell from companies like Ring, August or Doorbird. A simple smartphone app will allow you to see and speak to the person at your door. We did a review of the NEST Outdoor Camera in 2017. Check out the article here.
We always recommend wiring for these systems so you don’t have to worry about running power or using batteries. For new construction, this is straight forward and doesn’t cost a lot when the walls are open.
For your smart home integrated solution, look at the Control4 door stations which are elegant and very quick responding. Simple to use, they automatically show up on your devices and can even pop up on your TVs.