How do you think Microsoft does Office on Android and iOS?
As for verification, they have plenty of talks at CppCon and BUILD about how they do it.
EDIT: to save you some work.
CppCon 2014: Zaika Antoun "Microsoft w/ C++ to Deliver Office Across Different Platforms, Part I"
https://www.youtube.com/watch?v=3HROqnw-nf4
CppCon 2014: Zaika Antoun "Microsoft w/ C++ to Deliver Office Across Different Platforms, Part II"
https://www.youtube.com/watch?v=MGMoRu5yrVc
Reacting to Dropbox: another take on cross-platform C++ development
https://dev.to/tanker/reacting-to-dropbox-another-take-on-cr...
Ashampoo Systems GmbH
Looks cool on paper. Anybody around has experience with it ?
If serious, well then web dev deserves its reputation.