Using the same backend for both mobile and web applications?

I want to develop an app which works for both web and mobile.I have developed an android app before using android studio. But this time i want to have the same backend for both mobile and web, so i decided to use nodejs for the back end and angular and react for the web front end. My question is what exactly do i need for this app to work on the android app as well? Will i need 2 back ends to develop my android app?