Oleksandr Rabinovych, Google Material Design Developer in Svishtov, Bulgaria
Oleksandr Rabinovych

Google Material Design Developer in Svishtov, Bulgaria

Member since February 1, 2016
Oleksandr has developed many sophisticated Android projects as well as some web projects and apps for embedded systems. He is a talented, creative expert in his field who loves tasks requiring lateral thinking. He is also a quick study who loves tackling new tech. At the same time, Oleksandr is an easy-going and understanding person which greatly contributes to an enjoyable and cooperative work atmosphere when working with others.
Oleksandr is now available for hire


  • HypeLabs (via Toptal)
    Android, Java, Bluetooth LE, Mesh Networking, Java Concurrency...
  • Stilling
    Kotlin, Android, Model View Viewmodel (MVVM), Coroutines, SVG...
  • PrivateWifi
    Android, Java, Kotlin, VPN, Git, Phabricator, Robospice, Debugging, Flavors...



Svishtov, Bulgaria



Preferred Environment

Mercurial, Git, Eclipse, Android Studio, Linux

The most amazing...

...project I've worked on was an Android client for a service which uses artificial intelligence to transform boring camera videos into exciting movies.


  • Android Developer

    2022 - 2022
    HypeLabs (via Toptal)
    • Developed an Android SDK in Java for creating mesh networks via BLE for facilitating internet transactions by devices with limited connectivity.
    • Implemented device disappearance and internet connectivity state propagation via a mesh network.
    • Stabilized the Java codebase by improving its thread safety.
    Technologies: Android, Java, Bluetooth LE, Mesh Networking, Java Concurrency, Concurrent Programming
  • Android Developer

    2020 - 2021
    • Created an app that allows technicians to find a car's model from the catalog or its license plate and then order parts for it.
    • Supervised the work of an intern developer who covered the project with tests and added some new functionality.
    • Integrated the Phrase service to maintain the app's translation into more than 10 languages.
    • Created an app for Zebra tablet that is able to scan products' barcodes and make an order via the shop's API.
    Technologies: Kotlin, Android, Model View Viewmodel (MVVM), Coroutines, SVG, Android Material Design, Zebra EMDK, Barcode Reader, Phrase, Trello, Mobile Development, REST APIs
  • Android Developer

    2019 - 2021
    • Developed an app in Kotlin from the ground up that changes the client's DNS address and demonstrates the data compression capabilities of the company's service by playing YouTube videos.
    • Maintained an SDK for making apps that connect to the company's VPN.
    • Maintained documentation for the above-mentioned SDK's API.
    • Refactored the source code for an app that helps to reduce users' mobile traffic.
    • Debugged and added new functionality for different flavors (brandings) of the company's Android app for connecting to their VPN based on network conditions—mobile data, secure and insecure WiFi.
    • Updated the apps' target API level to meet the requirements of Google Play.
    Technologies: Android, Java, Kotlin, VPN, Git, Phabricator, Robospice, Debugging, Flavors, Gradle, WorkManager API, EventBus, Model View Viewmodel (MVVM), Widgets, Mobile Development
  • Android Developer

    2019 - 2020
    Starlink Pharma SAS (via Toptal)
    • Added a few features (including barcode scanning functionality) to an existing Android app.
    Technologies: Java, Kotlin, Android, Mobile Development
  • Kotlin Android Developer

    2018 - 2019
    • Added new features to two existing Android apps.
    • Incorporated Jetpack libraries into project.
    • Integrated dependency injection framework (Dagger2).
    • Helped to migrate from Realm to RoomDB.
    Technologies: RxJava, RoomDB, Model View Viewmodel (MVVM), GraphQL, Kotlin, Android, Mobile Development
  • Freelance Android Developer with Strong Cryptography Experience

    2018 - 2018
    NDA Client (via Toptal)
    • Implemented an Android app from the groundup to deal with Ethereum transactions.
    Technologies: AES, QR Codes, Cryptocurrency, Ethereum, Web3.js, Kotlin, Android, Mobile Development
  • Freelance Android Developer

    2018 - 2018
    Rehash, LLC (via Toptal)
    • Created custom Android component (Draft.js editor) for React Native.
    • Fixed bugs in a React Native app.
    Technologies: Draft.js, Android, JavaScript, Kotlin, Java, React Native, Mobile Development
  • Freelance Mobile App Developer

    2018 - 2018
    POMCO (via Toptal)
    • Refactored an Android app.
    • Updated the UI and added animations.
    • Improved reliability of the Bluetooth connection.
    • Added support for the newest Android versions.
    Technologies: Bluetooth, Android Data Binding, Android, Java, Mobile Development
  • Freelance Android Developer

    2018 - 2018
    Codecacao (via Toptal)
    • Enhanced and supported the existing Android app.
    Technologies: Android, Kotlin, Mobile Development
  • Android Developer

    2017 - 2018
    • Supported an Android messenger app.
    • Fixed chat latency and connection reliability issues.
    Technologies: Mongoose, XMPP, Java, Android, Mobile Development
  • Android Developer

    2017 - 2017
    UP Project Developments
    • Developed a voice recorder from scratch.
    • Built a simple Material Design UI.
    • Facilitated the auto sending of recorded files via SMTP.
    Technologies: SMTP, Audio Recording, Java 8, Rx, Reactive Programming, Android, Mobile Development
  • Freelance JavaScript Expert

    2017 - 2017
    MICA (via Toptal)
    • Supported user scripts for automating work with Google Spreadsheets.
    • Added new features using GAS.
    Technologies: Spreadsheets, Google Apps Script, JavaScript, Google Sheets
  • Android Developer

    2017 - 2017
    Confidential Company
    • Supported an Android client app with embedded photo taking and recognition.
    Technologies: Model View Presenter (MVP), DBFlow, Retrofit, Android Camera App, RxJava 2, Android Data Binding, Android, Mobile Development
  • Freelance Android Developer

    2016 - 2017
    BioMetrix (via Toptal)
    • Created an Android app (from scratch) that communicated with peripheral devices via Bluetooth.
    • Contributed to the creation of the UX and design for the app.
    • Implemented a time-synchronization protocol with a 10-millisecond precision.
    • Implemented BT communication data recovery logic.
    Technologies: Animated GIFs, Amazon Web Services (AWS), Retrofit, Bluetooth, Android, Mobile Development
  • Android Developer

    2016 - 2016
    • Supported an Android app that shows funny animated reminders about missed calls, events, emails, IMs, and more.
    Technologies: Accessibility, Android, Mobile Development
  • Android Developer

    2016 - 2016
    • Created an Android mobile client application for a playlist management web-service.
    • Implemented a custom design.
    Technologies: Realm, Audio Streaming, Android, Mobile Development
  • Freelance Android Developper

    2016 - 2016
    Uprise (via Toptal)
    • Created an Android app for data visualization from scratch.
    • Used a chart graphical library to display data from weather stations.
    Technologies: Android, Java, Mobile Development
  • Freelance Android Developer

    2016 - 2016
    MCProHosting (via Toptal)
    • Fixed bugs and added a new functionality to an Android client for viewing live streams.
    • Added RTMP video-streaming support.
    • Changed the existing UI to make it compliant with the material design.
    • Helped to integrate the app with Google Cast.
    Technologies: Real-time Messaging Protocol (RTMP), HTTP Live Streaming (HLS), Video Streaming, WebSockets, Android, Java, Mobile Development
  • Android Java Developer

    2015 - 2015
    Jank Studios
    • Developed a social media app for Android.
    • Integrated Facebook, Twitter, and Instagram networks into the app.
    Technologies: Instagram, Twitter, Facebook, JSON, REST, Java, Android, Mobile Development
  • Android Java Developer

    2015 - 2015
    Raul Marco (Private Customer)
    • Created an app for picking assigned locations for your contacts on your Android device.
    Technologies: SQLite, Java SE, Android, Mobile Development
  • Android Java Developer

    2015 - 2015
    • Added modifications to an existing open-source Android app to change its behavior.
    • Redesigned the brand for the above mentioned app.
    Technologies: HTML Parsing, Java SE, Android, Mobile Development
  • PhoneGap Developer

    2015 - 2015
    Yevhen Teneta (Private Customer)
    • Created a prototype of an animated audio-book reader app for Android and iOS using PhoneGap.
    Technologies: CSS, JavaScript, HTML5, Cordova, PhoneGap, Mobile Development
  • Java Developer

    2012 - 2015
    ELEKS Software
    • Developed a web app that manages cloud computers from AWS; this involved using J2EE/Spring stack for the back end and HTML/JavaScript/CSS for the front end.
    • Created a mobile app for contacting people inside a company using Scala for Android.
    • Supported an Android time-tracking app using Java and SQLite.
    • Built an Android market-type app using Java and implementing Material Design.
    • Maintained and tested PDF-rendering component of a web-service using Java.
    • Supported a Blackberry legacy time-tracking project using J2ME.
    Technologies: Amazon Web Services (AWS), Mercurial, Scala, JPA, Bootstrap, jQuery, Ajax, CSS, JavaScript, HTML, EclipseLink, Spring, Java EE, ORMLite, SQLite, Java SE, Android, Mobile Development
  • Java Mobile Developer | Lua Developer

    2011 - 2012
    • Developed a smart-card emulator for Blackberry smartphones using Java ME.
    • Created a UI framework for TV applications with Lua script.
    • Built a testing framework using Lua.
    • Wrote unit tests for a framework running in an embedded system.
    • Developed the UI and business logic for a native Android app related to video processing.
    • Debugged and modified a Bouncy Castle library for working with cryptographic entities.
    • Created a video-player demo application with Lua scripting.
    Technologies: Subversion (SVN), Lua, Android, PKCS, BlackBerry, Java ME, Java SE, Mobile Development


  • Magisto

    The project is about auto-beautifying videos from your Android camera. It consists of a client and a server (pretty obvious). The server was developed on the customer’s side whereas we developed the Android client. No specific custom technologies were used, but we used many different parts of Android SDK (probably, the one we did not use was a database).

  • Beam

    My client wanted me to improve the existing live-streaming Android app by fixing some bugs and adding new features.

    The work included working with WebSockets, using 3rd-party library to view RTMP streams, adding a functionality that required an integration with new server APIs, and changing the app's UI to implement Material Design.

    My client and end-users were satisfied with the app and the app's rating has increased since I worked on the project.

  • Aggreg8

    My client wanted an Android app to enable users to follow their favorite public figures on different social media networks in one place. So instead of switching back and forth between Facebook, Twitter, and Instagram you can have a mixed timeline of everything.

    I implemented the app applying Material Design guidelines and the latest API guides suggestions. I integrated Facebook, Twitter, and Instagram APIs in a way that allowed me to manage them uniformly. The project required managing background tasks and using a SQLite database.

    It was a really nice experience.

  • iEnigma

    The target product was a kind of smart-card emulator. The idea is to use your mobile device as a security token (for example, to sign-in to Windows). Your device (BlackBerry, WinPhone, or Android) communicated with a so-called middle-layer via Bluetooth—exchanging some crypto-stuff such as keys, certificates, and more. The middle-layer in turn can be used by an end-user’s application to provide necessary security features.

    My role was to develop the Blackberry client.

  • Android SDK for Creating Mesh Networks

    An Android SDK for creating mesh networks via BLE. It enabled a device to send HTTP requests even if it was not currently connected to the internet directly. In such cases, the request would be forwarded via mesh to a device connected to the internet.

    I was an Android developer on the project and implemented device disappearance propagation, internet connectivity detection, and propagation. I also stabilized the project by adding thread-safety and improving BLE communication synchronization.


  • Languages

    Java 8, XML, Java, Google Apps Script, GraphQL, Kotlin, HTML5, SQL, Pascal, Bash, HTML, JavaScript, Java SE, Delphi, Scala, Lua, CSS, XHTML, TypeScript, Flavors
  • Frameworks

    Rx, AndroidAnnotations, ORMLite, JUnit, PhoneGap, Dagger 2, Glide, Bootstrap, Draft.js, JPA, Spring JDBC, Spring MVC, Spring, JavaServer Pages (JSP), Turn.js, Media Player, PowerMock, Mockito, Android SDK, React Native
  • Libraries/APIs

    RxJava 2, Retrofit 2, REST APIs, Android Universal Image Loader, AsyncTask, Google Gson, GSON, Android Support Library, LiveData, DBFlow, RxJava, MPAndroidChart, Butterknife, jQuery, Instagram API, Twitter API, Twitter SDK, Parse SDK, Facebook Open Graph API, Facebook SDK, SAX, Retrofit, AES, Apache HttpClient, Amazon API, Google Places API, Java Servlets, Quartz, Mobile HTML5, Google Maps, Google Maps SDK, OpenSSL, BouncyCastle, AtomPark SMS API, Android API, Web3.js, Robospice, WorkManager API
  • Tools

    Android Studio, Google Sheets, Java Concurrency, Google Docs, Chrome Developer Tools, Eclipse IDE, Android Jetpack, Logging, Jira, Subversion (SVN), Notepad++, Git, 9-patch, Mercurial, Microsoft Word, TortoiseSVN, VirtualBox, GitHub, Spreadsheets, Mongoose, Amazon EBS, Apache Tomcat, Servlet, Javadoc, Adobe Photoshop, AWS SES, Cron, FreeMarker, Microsoft Excel, Wireshark, VPN, Phabricator, Gradle, Trello
  • Paradigms

    RESTful Development, REST, Concurrent Programming, Generic Programming, Asynchronous Programming, Model View Viewmodel (MVVM), Mobile Development, Functional Programming, Object-relational Mapping (ORM), Model View Controller (MVC), Unit Testing, Real-time Messaging Protocol (RTMP), Model View Presenter (MVP), Reactive Programming, Model View Intent (MVI), MVC Design, Testing, PKCS, Manual Testing, Agile Software Development, Scrum, Android Material Design
  • Platforms

    JSE, Android, Android Oreo, Firebase, Linux, Linux Mint, Mobile, Parse, Java ME, Eclipse, Twitter, Ethereum, Amazon Web Services (AWS), Windows XP, Windows, BlackBerry, Amazon EC2, Java EE, Bluetooth LE
  • Storage

    Realm, SQLite, JSON, RoomDB, Relational Databases, Databases, MySQL, PostgreSQL
  • Other

    Android Data Binding, Debugging, Layout, EventBus, Memory Profiling, DOM, SMTP, Ajax, HTTPS, HTTP, Dom Manipulation, VCS, Google Material Design, Cordova, Android Animations, Apps, Writing & Editing, Mobile UX, Documentation, Encryption, Cryptography, Asymmetric Encryption, HTML Email, Email, HTML Parsing, Facebook, Instagram, HTTP Live Streaming (HLS), Accessibility, Animated GIFs, XMPP, Audio Recording, QR Codes, UI Animation, Audio Streaming, Android Camera App, Image Manipulation, MPch, EclipseLink, Video Capture, Video & Audio Processing, Video Editing, Videos, PDF, PDF Design, Checksum Calculation, Audio, Push Notifications, Digital Signatures, SSL Certificates, RSA, SSH, Bluetooth, DTD, RTMP, Video Streaming, WebSockets, SMS, Cryptocurrency, Cryptocurrency Payments, Coroutines, Widgets, SVG, Zebra EMDK, Barcode Reader, Phrase, Mesh Networking

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