I will write about my top 10 tools I think of as mandatory for developing high-quality Android applications. Keep in mind that this is a recommendation of tools that work for me and that other developers may use their own set of tools to achieve different goals.
1. Android Studio
In order to start the development of an Android application, the first thing you need to download is Android Studio. Android Studio provides a unified environment where you can build apps for Android phones, tablets, Android Wear, Android TV, and Android Auto (to be more precise, any device that runs Android as the primary OS). It also covers Android Emulators, which are virtual machines over which we can run and test our app; we will talk about it later.
Android Studio IDE makes it easy to create Android apps for various form factors, such as handsets, tablets, TV, and Wear devices. You can download Android Studio from the official web page. It runs on Windows, Linux, Mac, and Chrome OS. https://developer.android.com/studio
System requirements are different for each OS, so I suggest checking it on the official site I have provided above. Just a note, you don’t need any particular configuration for it. You don’t need a powerful machine to run it on; there will be a difference only in performance, which is expected.
2.Gradle
The Android Studio build system is based on Gradle, and the Android Gradle plugin adds several features specific to building Android apps. It can run independently of Android Studio and be updated separately. Gradle is a build system responsible for code compilation, testing, deployment, and conversion of the code into .dex files and hence running the app on the device, in this case, Android device.
Whenever you click on the Run button in Android Studio, a Gradle task automatically triggers and starts building the project. After Gradle completes its job, the app starts running in AVD or in the device connected over the USB or Wi-Fi.
There are two build.gradle files for every Android Studio project. One is for the application, and the other is for project-level (module-level) build files where you can manage the specific setup for each.
build.gradle (project level)
The Top-level (module) build.gradle file is a project-level build file, which defines build configurations at the project level. This file applies configurations to all the modules in the Android application project.
build.gradle (application level)
The Application level build.gradle file is located in each module of the android project. This file includes your package name as applicationID, version name (APK version), version code, minimum and target SDK for a specific application module. When you use external libraries, you need to mention them in the app level Gradle file to include them in your project as dependencies of the application.
You can find more info about the Gradle Android, including release notes here. https://developer.android.com/studio/releases/gradle-plugin
3. Localazy
Most developers struggle with the localization of their apps. Finding an ideal solution is always tricky, but I have found a little treasure. Localazy is relatively new out there, but believe it or not - it can easily compare with the other similar tools already in the market for a while, and some of them have existed for a decade now.
Localazy is a feature-rich translation management platform that allows you to handle the translation process easily, making it straightforward for your user base to opt-in and provides plenty of solutions for you as a developer and your project. Localazy is more than suitable for any Android developer in need of localization management. The founder is a succesful Android developer himself!
Localazy also offers many valuable features - for example:
- OTA updates that deliver your fresh translations without you having to touch the source code.
- The ShareTM technology that helps translate your apps with shared translations.
- A variety of localization services such as the Virtual Translator that can make your life as a multilingual app developer a lot easier.
It just suits all the needs! And one important thing, it’s very affordable, unlike others 
4. Firebase
As they said, “Backed by Google and loved by app development teams - from startups to global enterprises,” Firebase is an ideal solution to run high-quality apps on. It offers features like Firebase databases, machine learning infrastructure, hosting and storage solutions, analytics, crashlytics, Cloud Functions, and more.
You should definitely check this link: https://firebase.google.com/
Here, I will cover just a few of them I think are essential and which I use.
Realtime DBStore and sync data with a NoSQL cloud database. Data is synced across all clients in real-time and remains available when your app goes offline. The Firebase Realtime Database is cloud-hosted. Data is stored as JSON and synchronized in real-time to every connected client.
AnalyticsGoogle Analytics is a free app measurement solution that provides insight into app usage and user engagement. It is a helpful tool to understand how and from where people use your app. The detailed insights enable you to make informed decisions regarding app marketing and performance optimizations.
CrashlyticsFirebase Crashlytics is a lightweight, real-time crash reporter that helps you track, prioritize, and fix stability issues that erode your app quality. Crashlytics saves you troubleshooting time by intelligently grouping crashes and highlighting the circumstances that lead up to them. It will help uncover what causes your apps to crash and find an ideal solution to improve user experience.
5. Instabug
Instabug aims to help the developer collect performance metrics, crash reports, and many other kinds of valuable logs. Some developers found it more suitable than Firebase because it’s more dedicated to the features it offers. Instabug instantly notifies you whenever there’s a problem in your app through comprehensive bug and crash reports and performance metrics.
Receive console logs, network logs, and visual repro steps to debug issues easily, saving you time investigating, diagnosing, and resolving problems.
Read more about the features and integration on the official webpage https://instabug.com/
6. Bitrise
Bitrise is a powerful automation tool for development, testing, and deploying builds. It’s definitely a time-saver; automating the whole development/testing process increases your software product quality and saves a lot of time for you and your team. It is a “needed” tool for dev teams where there are more than two developers.
Doing this all by manual methods will undoubtedly lead to a mess inside the code, failed builds, and so on, making the process unnecessarily time-consuming, especially if it’s a big project. Continuous integration, delivery, and deployment are one of the top benefits of Bitrise.
Read an article on Automated localization with Bitrise and Localazy or check the official website for the integration docs and feature list.
7. Android Emulator
The Android Emulator simulates Android devices on your computer to help you test your application on a variety of devices and Android API levels without needing each physical device. The emulator provides almost all of the capabilities of an actual Android device, including simulation of different device states and hardware configurations. You can run this emulator from Android studio and test your app away faster than you could do with a physical device.
Read more about it and how to use it on https://developer.android.com/studio/run/emulator
8. Appcenter
Appcenter is a cross-platform tool that lets you automate and manage the lifecycle of your iOS, Android, Windows, and macOS apps and many more.
Connect your repo and, within minutes, automate your builds, test on real devices in the cloud, distribute apps to beta testers, and monitor real-world usage with crash and analytics data. All in one place.
It’s easy to set up and supports many widely used git solutions. Connect to GitHub, Bitbucket, GitLab, or Azure DevOps and build your app in the cloud on every commit. Automatically run unit tests, release to testers and stores, or test your UI on real devices.
More on https://appcenter.ms/
9. AdMob
We all know that Android app developers don’t earn money based on download counts, reviews, and pleasant words from the users. Those are just a few critical factors that will help generate more revenue from apps with some form of app monetization.
AdMob is the most famous and widely used. Your hard work will be definitely rewarded. AdMob makes earning revenue easy with in-app ads, actionable insights, and powerful, easy-to-use tools that grow your app business. It’s easy to integrate, cross-platform, and well documented.
Get more info about integration, feature list, and solutions on https://admob.google.com/
10. Facebook Audience Network
Facebook audience network is also an ad serving solution for your apps. It’s cross-platform, offers multiple ad types, and it binds to the Facebook ecosystem itself. Facebook audience network is also one of the top used solutions because of its rich content nature.
From what I’ve learned over the past few years being in doubt about which service to use, I found that this one has slightly better income for the developer, but it’s not for newly baked apps since it requires some threshold of users to start serving ads.
Read more on https://www.facebook.com/audiencenetwork/
Conclusion
I hope you have checked all of the suggested tools and found some that suit your needs. Keep searching and evolving; this is an ongoing thing. Every day brings us new solutions, new tools, and also obstacles.
Do you have any other tools & tips worth consideration? Please share with us your tips & tricks on Android devtools in our discussion forum. 
Cheers!
This is a companion discussion topic for the original entry at https://localazy.com/blog/top-10-tools-multilingual-android-development