Dmitry Ryazantsev, Developer in Budva, Montenegro
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Dmitry Ryazantsev

Verified Expert  in Engineering

Android Developer

Budva, Montenegro
Toptal Member Since
April 18, 2016

Dmitry is an Android developer with more than six years of experience who communicates well and always tries to find the best tech that suits the project. He's experienced with Git, Lua (Corona SDK), RxJava, and Dagger. He's worked with a large team to develop the Yandex browser with more than 10 million installations. He's also developed his own projects—a game with 250,000 installations and published several other apps.


Android SDK, Kotlin, Android, Identity, Continuous Deployment...
Freelance Work
Mobile Applications, Mobile Development, Android SDK, Robolectric, JUnit...
Emirates (via Toptal)
Mobile Applications, Mobile Development, Android, Android SDK, RxJava, Realm...




Preferred Environment

MacOS, Linux, Git, Android Studio, CircleCI

The most amazing...

...things I've worked on are the Yandex browser with more than 10 million installs and a solo project, the Draw & Ride Android game with 250,000+ installs.

Work Experience

Lead Android Developer

2018 - PRESENT
  • Built the overall process of Android development inside the company.
  • Prepared complex multi-module and multi-project build configurations with CI/CD involved.
  • Built a multi-module project with complex dependencies.
  • Set up the configuration to build multiple apps out of the single codebase.
  • Created a reliable codebase covered by unit tests that run for each PR.
Technologies: Android SDK, Kotlin, Android, Identity, Continuous Deployment, Continuous Integration (CI), Continuous Delivery (CD), Unit Testing, POS, Point of Sale, Payment APIs, Android Oreo

Android Developer

2010 - PRESENT
Freelance Work
  • Created an Android game with physics that has 250,000 plus installations.
  • Developed an Android game that also has iOS and HTML5 versions and was popular in Asia (Japan and Korea).
  • Built a system for a synchronization of contacts and birthdays for a popular Russian social network VK (formerly Vkontakte); even before the first official app was created.
  • Assembled a team to develop my apps: designers and one other developer.
  • Created several apps (REST clients) as an independent contractor.
  • Wrote a custom hand-drawing algorithm that let users draw physics object on the screen and erase part of them.
  • Built an app that synchronized users' birthdays from Vkontakte that uses a private Android API.
Technologies: Mobile Applications, Mobile Development, Android SDK, Robolectric, JUnit, Gradle, Dagger, Retrofit, RxJava, Robospice, Bitbucket, Git, Lua, MySQL, PHP, Android, Java, Android Oreo

Senior Android Developer

2016 - 2017
Emirates (via Toptal)
  • Supported the existed code and improved the architecture.
  • Wrote tests on the essential parts of the existed code.
  • Developed a custom session renewal mechanism.
  • Created a Facebook-like feed with custom cards inside.
  • Implemented a bidding system that allows the user to bid miles for real goods.
Technologies: Mobile Applications, Mobile Development, Android, Android SDK, RxJava, Realm, Java

Android Developer

2013 - 2016
Yandex LLC
  • Created a smoothly animated shuffle algorithm for a grid view with a drag-and-drop mechanism.
  • Held interviews for open positions under different topics like architecture, Java, algorithms, and Android.
  • Made speeches at mobile conferences in Yandex-specific conferences and others.
  • Created the infrastructure for project documentation.
  • Built several features from scratch and also the custom user interfaces for them.
Technologies: Mobile Applications, Mobile Development, Android SDK, Robolectric, JUnit, Clang, Agile, TeamCity, Stash, Jira, Git, Android, Java

Android Developer

2012 - 2013
  • Created a library for XML digital signatures for Android developers.
  • Wrote dozen of tests for Crypto providers.
  • Created an Android Crypto provider for Android developers.
  • Built a test environment with CORBA.
  • Managed a continuous integration process.
Technologies: Mobile Applications, Mobile Development, Android SDK, Crypto, Security, Android, Java

Android Developer

2012 - 2012
  • Wrote an algorithm to paint different zones on texture when the user touches it; used OpenGL.
  • Built an UI to place images above other images (with rotation and scaling) and the ability to save to an Android device.
  • Created a messenger for the Russian social network site VK (formerly Vkontake) in order to beat the competition.
  • Designed a custom interface with smart-text wrapping.
  • Built an Android app for a popular Russian company (a catalog for realty firms).
Technologies: Mobile Applications, Mobile Development, Android SDK, REST APIs, OpenGL, Subversion (SVN), Android, Java

Sonect Android Apps
I created a multimodule complex app that lets people withdraw money in local shops, bakeries, and more. I built the process of Android development which involves CI/CD, testing, and deploying, and also led the android team which delivers android apps.

Phrase of the Day
This app provides positive thinking for every day; it also has widgets for the Android desktop and an app for the Android watch.

Skippy the Traveler

This is an Android puzzle game built with Lua; there are also iOS and HTML5 versions.

Tray Notes
This is one of my first apps; it's an easy way to create reminders in notifications.


A small game that was created after the success of the Flappy Bird game with Corona SDK.

Magic Runes

I created the first version of the app for rune lovers. This app gives you the ability to put runes on your photos and save it to your gallery.

Partner ID

A REST client for the web service; Robospice and Retrofit are used in the app and Partner ID lets you check your contractors.

Yandex Browser
The browser is built above Chromium and has its own native part (C++) and Java code. It has more than 10,000,000 installs.

Draw and Ride
An Android puzzle game with physics. The user can ride on a hand-drawn road. This game was popular in Korea (not via Google Play) and has 250,000 plus installs in Google Play other than in Korea.

This game took a part in a worldwide competition AppCircus.

A content-based project about Android development that includes a blog, Telegram, Vkontake and Facebook channels. I write articles and share brief posts about overall mobile development process.



Flutter-based mobile apps that let users scan receipts and get cashback from buying construction materials. I built cross-platform apps for iOS and Android and set up the delivery process to the markets. I led the overall project and organized back-end and backoffice development.
2007 - 2012

Bachelor of Science Degree in Computer Science

Moscow State University - Moscow, Russia


Butterknife, Firebase Android SDK, Android Support Library, Google APIs, REST APIs, Retrofit, Retrofit 2, VK API, Android API, Accelerometers, Libraries/APIs, Fabric, Google Play API, Picasso, Google API, RxJava 2, VKontakte API, Android Universal Image Loader, Android Design Library, RxJava, Robospice, Yandex Maps API, Facebook API, OpenGL,, Android OpenGL, Volley Android Library, Mixpanel Android API, Mixpanel API, Zendesk API, Yandex API


IDEA IDE, Firebase Analytics, Android Studio, Git, Trello, Android Debug Bridge, Android Device Manager, Skype, Crashlytics, Slack, Wrike, Asana, RealtimeBoard, Zeplin, CircleCI, Firebase Cloud Messaging (FCM), Microsoft Excel, Excel 2007, Excel 2016, Excel 2010, Spreadsheets, Corel VideoStudio, Adobe Premiere Pro, GitHub, Gradle, RxAndroid, VKontakte SDK, Twitter Android SDK, Facebook Android SDK, IntelliJ IDEA, Bitbucket, Adobe Photoshop, Jira, Stash, TeamCity, Subversion (SVN), Figma, Google Analytics, Android NDK, Instabug, Adobe CC, Adobe, Photoshop 2017, Photoshop CS3, Photoshop CS6, Photoshop 2015, Photoshop 2014, Photoshop CC, Photoshop CS5, Photoshop 7, Sketch, Sketch 4, Sketch 2, Sketch 3


Android SDK, Rx, Dagger 2, Play SDK, AndEngine, JUnit, Robolectric, Dagger, Flutter, React Native, Espresso, Glide, PowerMock, Mockito, Roboelectric Testing Framework, Corona SDK


Kotlin, Java, Java 7, Java 8, Java 6, Java 9, SQL, PHP, JavaScript, Lua


Object-oriented Programming (OOP), Mobile Development, RESTful Development, REST, Model View Presenter (MVP), Continuous Deployment, Continuous Delivery (CD), Continuous Integration (CI), App Development, Test Automation, Mobile App Design, Automated Testing, Agile Workflow, Agile, Android Material Design, Scrum, Model View ViewModel (MVVM), Model View Controller (MVC), Agile Software Development, Functional Programming, UI Design, Continuous Development (CD), Unit Testing, Test-driven Development (TDD), Photoshop Design


Mobile, Android, Firebase, Linux, iOS, AppsFlyer, Android Oreo, Android Watch, Mixpanel, Zendesk, MacOS, Eclipse, Ubuntu, Ubuntu Linux, Amazon Web Services (AWS)

Industry Expertise



SQLite, MySQL, Realm


Google Play Store, App UI, Apps, Mobile App Development, HTTP REST, RESTful Services, Mobile App UI, Mobile Applications, Computer Science, Computer Skills, Mobile UX, Layout, Mobile App Testing, Mobile UI, APIs, Writing & Editing, User Experience (UX), Android Theming, Android Style Guidelines, Libraries, UI Animation, App UX, OkHttp, Analytics, Slack App, GUI Development, RESTful Web Services, Android Performance Optimization, Android Emulators, Android Development, Git Forks, GitKraken, Git GUI, Computer Security, Browsers, Cross-platform App Development, MacBook, SDKs, Android Camera App, Android Components, Android Testing, Android UI Design, Android Guides, Android App Design, Android Design Guidelines, Android Data Binding, Android Screens, GitFlow, Security, Clang, Crypto, Amplitude, Segment, Urban Airship, Leads, Data, Data Structures, Algorithms, Push Notifications, Bluetooth, Game Development, Mobile GPS, GPS, Near-field Communication (NFC), Hybrid Apps, Android Internals, Android Game Development, Android Games, Android Wear, Test Automation Frameworks, Automated UI Testing, Identity, POS, Point of Sale, Payment APIs, User Interface (UI), Localization

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