Apps are practical, mostly free and very popular. But almost all commonly used apps surreptitiously collect sensitive personal data and send them to their developers. But alternatives are available.
Many apps on the market, in particular for the Android operating system, have been specially designed not to collect user data. Wire is a secure alternative to messaging services like WhatsApp. The developers have even released the source code. Transportr is a collaborative project designed to let travelers plan their trips with the aid of public transportation. And the free e-mail program K-9 has been downloaded millions of times so far.