Oleksii is available for hire
Hire OleksiiOleksii Masnyi
Verified Expert in Engineering
Android Developer
Zadar, Croatia
Toptal member since August 6, 2015
Bio
Oleksii is an ex-Facebook senior software engineer who's shipped dozens of Android apps for billions of people. Oleksii has experience building products and teams from the ground up as well as getting into a huge legacy codebase, making dramatic performance improvements and aligning the development processes in existing teams. Oleksii combines leading and architectural skills, product vision and passion to testing, design and user experience to make truly awesome products.
Portfolio
Hopper
Android, Google Play Store
Facebook
Java, Android, SQLite, Kotlin, Dagger 2, Mercurial, Git, A/B Testing...
Geneva Chat
Android, Kotlin, Coroutines, Dagger 2, Retrofit 2, RxJava 2, SQLite...
Experience
- Java - 14 years
- Android - 11 years
- Kotlin - 8 years
- Bluetooth - 3 years
- Coroutines - 3 years
- TensorFlow - 1 year
- Dart - 1 year
- Flutter - 1 year
Availability
Full-time
Preferred Environment
Git, Gradle, Android Studio, Kotlin, Android SDK, Android, Bluetooth, Java, Coroutines, Firebase
The most amazing...
...solutions I've built are photo annotation tools for WhatsApp which meet performance constraints for billions of Android devices.
Work Experience
Lead Android Engineer
2022 - 2023
Hopper
- Led payments development on Android, crafting a payment component and significantly improving payment conversion rates.
- Introduced alternative payment methods (PayPal and Klarna), resulting in a revenue increase amounting to hundreds of thousands of dollars.
- Enhanced payment system efficiency and user experience on Android, contributing to the revenue boost.
- Mentored and guided a team of Android engineers, fostering increased productivity and skill development.
Technologies: Android, Google Play Store
Senior Software Engineer
2021 - 2022
- Shipped improvements for camera and status at WhatsApp Android for 2+ billion users, which significantly increased privacy and improved user experience.
- Developed a new version of the media composer, including a new blur pen tool that met performance constraints for billions of Android devices.
- Implemented performance metrics for one of the core WhatsApp features.
Technologies: Java, Android, SQLite, Kotlin, Dagger 2, Mercurial, Git, A/B Testing, Performance, User Interface (UI), Espresso, MacOS, OS X, Android SDK, Android Studio, Architecture, API Architecture, Mobile App Development, Technical Leadership, Software Project Management, Unit Testing, JUnit, Continuous Integration (CI), Product Management, UX Wireframes, Mobile, Widgets, Camera SDK, APK, Sideloading, User Experience (UX), Camera2 API, Android Camera App, Google Play Store
Lead Android Engineer
2020 - 2021
Geneva Chat
- Introduced the Model–View–ViewModel (MVVM) architecture and Kotlin coroutines across the codebase, significantly increasing the testability and stability of the Android app.
- Refactored the core app components, increasing the velocity of sending and receiving messages by 5x.
- Led a small development team to follow better engineering practices, code reviews, continuous integration (CI), and testing.
Technologies: Android, Kotlin, Coroutines, Dagger 2, Retrofit 2, RxJava 2, SQLite, User Interface (UI), Retrofit, Espresso, RxJava, Google Cloud Messaging, Google Material Design, MacOS, OS X, Android SDK, Java, Android Studio, Architecture, API Architecture, Mobile App Development, REST APIs, Technical Leadership, Software Project Management, Unit Testing, JUnit, Continuous Integration (CI), Product Management, UX Wireframes, Mobile, APIs, Widgets, Swift, REST, APK, Sideloading, User Experience (UX), GraphQL, WebSockets, Google Play Store
Senior Android Engineer
2015 - 2020
MetaLab
- Developed an Android app to integrate with robotic hardware using Bluetooth Low Energy.
- Built an app leveraging ARCore technology to visualize custom 3D models.
- Used TensorFlow to build and train various machine learning models in making UI predictions.
- Led the Android team and introduced the MVVM architecture and Kotlin coroutines. Established the best engineering practices to improve testing, code reviews, and CI.
- Developed the first async/await open source library to leverage Kotlin coroutines for Android.
Technologies: Android, Flutter, Java, Kotlin, Coroutines, Dart, Python, TensorFlow, RxJava 2, Dagger 2, Bluetooth Low Energy (LE), ARCore, User Interface (UI), Retrofit, Espresso, RxJava, Google Cloud Messaging, Augmented Reality (AR), Google Material Design, MacOS, OS X, Android SDK, Android Studio, Architecture, API Architecture, iOS, Mobile App Development, REST APIs, Technical Leadership, Software Project Management, Unit Testing, JUnit, Continuous Integration (CI), Product Management, UX Wireframes, Mobile, APIs, Widgets, Swift, REST, APK, Sideloading, User Experience (UX), Google Play Store
Senior Android Engineer
2013 - 2015
Sony
- Integrated the rich communication services (RCS) chat client protocol into the messaging app.
- Supported the phone and tablet platform migration on Android Lollipop.
- Improved various system apps to follow material design guidelines.
- Created a library to simplify the background work handling with built-in caching.
- Guided a team on UI, performance, architecture refactoring, and improvements.
Technologies: Continuous Integration (CI), Code Review, Gradle, Git, Material Design, Android, Java, User Interface (UI), Espresso, Android Wearables, Google Material Design, MacOS, OS X, IntelliJ IDEA, Android SDK, Android Studio, Kotlin, Architecture, API Architecture, Mobile App Development, Technical Leadership, Unit Testing, JUnit, Mobile, APIs, Widgets, APK, Sideloading, User Experience (UX), Google Play Store
Android Engineer
2012 - 2013
Lohika
- Refactored a webcam Android app to support various device configurations.
- Redesigned the UI and improved usability in a webcam Android app.
- Developed a platform to host JavaScript web apps in a native Android container with built-in support for auto-update, offline mode, and push notification support.
Technologies: Continuous Integration (CI), Git, Apache Maven, Android, Java, User Interface (UI), JavaScript, MacOS, OS X, IntelliJ IDEA, Android SDK, Android Studio, Architecture, API Architecture, Mobile App Development, REST APIs, Unit Testing, JUnit, Product Management, UX Wireframes, Mobile, APIs, Widgets, REST, APK, Sideloading, User Experience (UX)
Android Engineer
2010 - 2012
Samsung
- Developed a TV remote-control Android app with video broadcasting using Android Native Development Kit (NDK) libraries and the Samsung TV SDK.
- Created an app to intelligently control Bluetooth speakers with an Advanced Audio Distribution Profile (A2DP).
- Built an app for group drawing and communication using a shared TV screen.
- Developed an efficient drawing UI from scratch to demo the new TV SDK.
- Improved the continuous integration process, increasing the app stability and the development process.
Technologies: Jenkins, Git, Apache Maven, NDK, Android, Java, User Interface (UI), Scala, Android NDK, IntelliJ IDEA, Android SDK, Android Studio, Architecture, API Architecture, Mobile App Development, REST APIs, Technical Leadership, Unit Testing, JUnit, Continuous Integration (CI), Product Management, UX Wireframes, Mobile, APIs, Widgets, REST, APK, Sideloading, User Experience (UX), Google Play Store
Java Developer
2008 - 2010
MTI
- Used the IBM WebSphere Business Integration Server for developing integration solutions to connect 10+ legacy enterprise applications, including enterprise resource planning (ERP) and warehouse management systems (WMS).
- Developed a new integration platform using Apache Karaf.
- Supported data migration between legacy enterprise systems.
Technologies: WebSphere, EventBus, Service-oriented Architecture (SOA), Java, SQL, Microsoft SQL Server, Oracle SQL, Unit Testing, JUnit
Experience
Paper
https://github.com/pilgr/PaperPaper is a fast and straightforward open-source NoSQL data storage library for Android that lets users save and restore Java objects by using efficient Kryo serialization and handling data structure that changes automatically.
AppDialer
An app that uses intelligent predictive search algorithms to search apps and contacts most efficiently. I'm the creator, UX designer, and sole developer of this app that I've done as a hobby. The app has two keyboard types—T9 and QWERTY.
WhatsApp allows users to get fast, simple, and secure messaging and calling, available for free on phones worldwide. I was improving the camera, status, and media composer components, increasing user privacy and enhancing the overall user experience.
Notenger
Flutter-based notes and reminder app, done in the style of a chat app. I had the original idea and the product's vision and made the development and shipped the app for Android and iOS (now discontinued).
Notenger leverages the commonly known design of the chat app to make adding notes and setting reminders as effortless as sending a message. Once a reminder is fired, it appears as an incoming message.
Notenger leverages the commonly known design of the chat app to make adding notes and setting reminders as effortless as sending a message. Once a reminder is fired, it appears as an incoming message.
Education
2000 - 2007
Master's Degree in Computer Science
National Technical University of Ukraine "Kyiv Polytechnic Institute" - Kyiv, Ukraine
Certifications
APRIL 2018 - PRESENT
Sequence Models
DeepLearning.AI
FEBRUARY 2018 - PRESENT
Convolutional Neural Networks
DeepLearning.AI
FEBRUARY 2018 - PRESENT
Structuring Machine Learning Projects
DeepLearning.AI
JANUARY 2018 - PRESENT
Improving Deep Neural Networks: Hyperparameter Tuning, Regularization, and Optimization
DeepLearning.AI
JANUARY 2018 - PRESENT
Neural Networks and Deep Learning
DeepLearning.AI
Skills
Libraries/APIs
RxJava 2, Retrofit 2, REST APIs, Retrofit, Camera2 API, NDK, RxJava, TensorFlow, PyTorch
Tools
Android Studio, Gradle, Git, Apache Maven, Mercurial, Jenkins, IntelliJ IDEA, Google Cloud Messaging, Android NDK
Languages
Java, Kotlin, SQL, Dart, GraphQL, Scala, JavaScript, Python, Swift
Frameworks
Android SDK, JUnit, Espresso, Flutter, Dagger 2
Paradigms
Continuous Integration (CI), API Architecture, Unit Testing, REST, Service-oriented Architecture (SOA)
Platforms
MacOS, OS X, Android, Bluetooth Low Energy (LE), Mobile, Firebase, ARCore, WebSphere, iOS
Storage
SQLite, Microsoft SQL Server, Oracle SQL
Other
Code Review, User Interface (UI), Bluetooth, Coroutines, Performance, Architecture, Mobile App Development, Technical Leadership, Software Project Management, Product Management, UX Wireframes, APIs, Widgets, APK, Sideloading, User Experience (UX), Google Play Store, Material Design, Google Material Design, Android Wearables, A/B Testing, Android Camera App, WebSockets, EventBus, Augmented Reality (AR), Machine Learning, Deep Learning, Camera SDK
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