Do single developer apps share data?

Question

iOS

for example, Yandex or Google has many applications, such as mail, maps, translator.
So, if I am logged in in one of the applications, then other applications also become logged in.
how does this happen?

Answer 1

In iOS, this happens through App Groups, applications can access the general settings in NSUserDefaults, most likely the token is saved and other applications use it.
here is a short tutorial on how to do it www.theappguruz.com/blog/ios8-app-groups

Answer 2

https://en.wikipedia.org/wiki/Single_sign-on