We use Kotlin as a main programming language (~98%). Kotlin | Getting started

We use suspend functions to write asynchronious code and *in a process of migrating the code from using a LiveData to using a Flow. * Coroutines | Getting started Kotlin coroutines on Android

We use Dagger 2 to manage the dependency injection. Dagger | Tutorial

We use Data binding to bind models to views. In a newer code we also use the newer ViewBinding and plan to migrate to it. Data Binding

We use a bunch of Android X libraries where the most interesting of those are:

1. Room database;
2. WorkManager to manage background tasks;
3. Play Core to provide different implmentations of the Map service for different countries;
4. Lifecycle to help to manage the lifecycle of the screens + LiveData.

We use GSON to parse the JSON into models although we are aware that there are better solutions now (looking at Moshi & Kotlinx Serialization).

We use Joda Time to avoid using of Java 7's date time APIs.

We use retrofit to create network API interfaces. Retrofit | Getting started

We use okhttp to send network requests.

We use a bunch of Firebase libraries: remote-config, messaging, auth, crashlytics, performance, ml-vision (to parse QR codes);