I work as an android developer using the Java language, I have used firebase for firestore databases, notifications, analytics, crashanalytics, etc. In addition, I have used dagger, Rest API, retrofit, Relm db, ObjectBox db, and other libraries. can be seen on the google play nfjuara application, there are several features that i have made in this nfjuara application, namely share scores, online courses, video streaming, and other bug fixes.