Hi Cat
I think Ring is Amazon but another option would be Google Hello doorbell.
I have a few Nest cameras and the alerts for people are pretty good.
You can set up two step verification on your account with a phone number meaning someone needs to be physically holding your phone in order to get the text code and log in. You can also check activity history periodically to make sure only devices you have specifically set can access you video feed.
Two step verification is a good thing to have across all you accounts.
Here's a nice vid explaining if you'd like to know more:
https://m.youtube.com/watch?v=hGRii5f_uScRegards
Mark
