Message: Howdy. I'm a coder who is feeling increasingly out-of-touch with the software world. I develop mostly server-side software/middleware in C, Perl, or Bash, but I haven't done frontend work since HTML 4.1 and I've never developed a mobile app. For a fun home project, I decided to try and reverse engineer my elliptical machine's proprietary bluetooth interface (rather than buying a yearly subscription to use the android app). The bluetooth bit is turning out to be the easy part, and now I'm looking to write an android app and maybe an iOS app for the wife's iPad. My question is this: is there a framework / paradigm for developing an app that can be compiled for both iOS and Android with minimal platform-specific code? I know C and perl, and I'm proficient with Bash, Java, and python. But I'm not opposed to learning a new language if necessary, however I've done just enough Dot Net work to never want to do it again. What is the most mainstream way of doing this? Something like Cordova? Is it reasonable to use a PWA to interface with the phone's bluetooth? Bonus points if you can get me a solution that lets me write it in C11.