pyswagger VS python-for-android

Yes exactly, adding a package to requirements is similar to doing a pip install on your regular Python. Look at pyswagger's requirements.txt and add them:

With that said the error is probably caused by something else, if you can't get it working post the complete build output with log_level=2. It could be an issue with your Java environment as per this issue https://github.com/kivy/python-for-android/issues/2790

I assume you are referring to Android here... The existing p4a build recipes are located in the pythonforandroid/recipes directory, you need make a grpc directory in this format.

You can't use any random library on Android, you are limited to pure python code and libraries with a build recipe for cross compilation. I am not familiar with the packages you try to use here, but probably there are no existing recipes and you'll need to provide that yourself to get it working (which, if I had to guess, is not going to be easy)

Build recipes are used to compile libraries for use on mobile platforms, see kivy-ios recipes directory and the corresponding python-for-android recipes directory. The quality varies here, some recipes may use outdated versions or provide limited library functionality. If you develop on Windows, you can install and use pretty much any Python package, but on mobile platforms, you are limited to those that are either 100% pure python, or have a build recipe.

figure out a recipe for buildozer. imo harder, as compiling is hell/we aren't trained to compile as python programmers. if you have C/C++ experience and have used make/clang before this route is for you. https://github.com/kivy/python-for-android/blob/develop/doc/source/recipes.rst

This should work as long as they are either pure python modules, or have a matching build recipe in python-for-android