Viacheslav

Personal information
Name: Viacheslav Khailenko
Phone number: [открыть контакты](см. выше в блоке «контактная информация»)
Date of birth: 27th November 1994
Email: [открыть контакты](см. выше в блоке «контактная информация»)
Telegram: https://t.me/eSlavik
Linkedin: [открыть контакты](см. выше в блоке «контактная информация»)

Senior Android Developer with 6 years of commercial experience building scalable and
high-quality Android applications. Strong expertise in Kotlin and Java, with a deep
understanding of software design principles and patterns, including OOP, SOLID, and
common Android architectural patterns.

Experienced across a wide range of Android technologies and frameworks, with extensive
hands-on experience in Jetpack Compose (4.5+ years) for building modern, maintainable,
and performant UI.

Technology Skills

Languages: Java, Kotlin

Tools and Technologies: Android SDK, Android Studio, IntelliJ IDEA

Stack of technologies:
●​ CI/CD pipelines: Azure, Bitbucket
●​ Jetpack Compose (4.5 years of commercial experience)
●​ Multithreading: Kotlin Coroutines, RxJava
●​ Android Jetpack libraries: Navigation component, Safe args, LiveData,
Paging library, ROOM, ViewModel, WorkManager, DataBinding, etc.)
●​ Dependency Injection: Dagger 2 (Hilt) / Koin
●​ Clean Architecture / MVVM / MVP / MVI
●​ Network: Retrofit2
●​ Databases: SQLite, Room / Realm
●​ Custom View
●​ Unit tests: JUnit / Robolectric
●​ Glide / Picasso
●​ Notifications
●​ Analytics: Datadog / Appsflyer / Google Analytics
●​ Firebase Services (Cloud Messaging, Remote Config, Firestore, Authentication,
Crahlytics)
●​ In-app billing (products and subscriptions)
●​ Google Maps, Meridian SDK
●​ BLE

Work experience
 ​NDA (product company)

Project: NDA (betting)

Duration: Aug. 2024 – Present

Technology Stack: Kotlin, Jetpack Compose, Kotlin Coroutines, MVI, Dagger2, Mockk,
StateFlow, Navigation Component, Remote configs, Clean Architecture, Modularized
app architecture, WorkManager, SQLite + legacy stack (Java)

Responsibilities:​
Worked as part of the Loyalty stream, responsible for the customer rewards program
(points, bonuses, and campaigns).

●​ Refactored and improved the legacy codebase (migrated from Java to Kotlin).
●​ Completed multiple tasks related to points accrual, redemption, and promotions.
●​ Promoted to stream lead for the Next Generation Loyalty (NGL) flow.
○​ Led planning sessions and syncs with developers, product, QA, and
design teams.
○​ Rebuilt the Rewards flow from scratch, including Main Rewards screen
with points balance, Reward Details screen with improved user
experience, New reward filtering and sorting logic.
●​ Migrated the flow to Jetpack Compose and MVI architecture, replacing the old
Java-based solution.
●​ Delivered the feature under a remote flag to ensure a safe production rollout.

Later, I was transferred to the Checkout & Transactions team for 3 months to support a
high workload.

●​ Focused on architectural improvements of the checkout flow.
●​ Extracted payment methods into a standalone feature module.
●​ Improved the Core module for better communication with payment features.
●​ Implemented a new payment method from scratch.
●​ Created documentation covering different payment scenarios to align Android,
iOS, and backend teams.

A-DIGITAL agency

Project: MDR App​
Duration: Feb. 2024 – Aug. 2024

Technology Stack: Jetpack Compose, Kotlin Coroutines, MVI, Koin, Retrofit,
SharedPreferences, Crashlytics, Zoomable, JUnit, Azure pipeline
Description:​
The MDR app is a comprehensive bike marketplace application created from scratch on
Compose. It offers a wide range of cycling services including bike selection, leasing
registration, theft reporting, repair requests, and a leasing calculator to facilitate
purchases.

Responsibilities:

●​ Developed the authorization flow to ensure secure user authentication.
●​ Implemented push notifications to keep users informed about important updates.
●​ Created search and filter functionality to enhance user experience and improve
accessibility.
●​ Developed a catalog with pagination and product cards to display bikes
efficiently.
●​ Integrated third-party services to extend app functionality.
●​ Built a leasing calculator to assist users with financial decisions related to bike
leasing.
●​ Covered code with unit tests to ensure high code quality and reliability.

DIGIS Agency

Project: Lexie (Healthcare app) // short-term project at DIGIS​
Duration: Nov. 2023 - Feb. 2024

Technology Stack: Kotlin, Dagger2, Android Jetpack Libraries, Kotlin Coroutines, MVVM,
Room, Firebase, BLE

Description:​
The Lexie app is an integral part of the Lexie Hearing experience, designed to enhance
the functionality of Lexie OTC hearing aids. It provides users with an intuitive resource
for managing their hearing health.

Responsibilities:

●​ Implemented the "Wearing Goals" feature to enhance user engagement.
○​ Registered new users in the Reward program.
○​ Integrated functionality to read-wearing data from hearing aids.
○​ Developed algorithms to perform specific calculations based on collected
data.
○​ Sent processed data to the server for further use.
●​ Improved code quality and resolved issues related to Bluetooth connectivity and
device pairing with hearing aids.
Project: ALmapa // short-term project at DIGIS​
Duration: Oct. 2023 - Nov. 2023

Technology Stack: Kotlin, MVI, Koin, Android Jetpack Libraries, Material Design,
Picasso, Clean Architecture, Firestore

Description:​
ALmapa is an application designed for people in Israel, providing functionality similar to
AirAlert in Ukraine but with broader capabilities. It allows users to easily track the
location of their loved ones in real-time and receive alerts based on their location. The
app provides updates if a family member enters a danger area, ensuring their safety and
peace of mind.

Responsibilities:

●​ Integrated Google Maps into the application for enhanced location tracking.
●​ Developed new features from scratch, contributing to the app's core functionality.
●​ Collaborated with the team to define and implement effective solutions.
●​ Implemented Firestore for efficient data storage and real-time updates.
●​ Designed and established the architecture for the project, ensuring a robust and
scalable structure.

Project: Dayinsure​
Duration: Nov. 2021 - Feb. 2024

Technology Stack: Kotlin, Java (refactoring legacy code to Kotlin), Kotlin Coroutines,
MVVM, WorkManager, Retrofit2, SQLite (Room), Koin, Custom View, JUnit, Android
Jetpack, Jetpack Compose (Profile Flow), Material Design, Glide, Clean Architecture,
Navigation Component & Safe Args, Notifications, Datadog, AppsFlyer, Crashlytics

Description:​
Dayinsure is one of the UK’s leading providers of short-term car insurance, offering
flexible and convenient insurance solutions for temporary coverage.

Responsibilities:

●​ Designed Android applications using various widgets such as RecyclerView,
Buttons, TextViews, Date and Time Picker, Range SeekBar, TextInputLayout, and
Custom Views.
●​ Developed new features including purchase flow, onboarding flow, and profile
flow.
 ●​ Collaborated with designers and backend engineers to create seamless user
experiences.
●​ Fixed bugs and improved application performance for a smoother user
experience.
●​ Built local unit tests achieving 70% coverage to ensure code quality and
reliability.
●​ Debugged critical issues such as crashes and memory leaks.
●​ Refactored legacy code from Java to Kotlin for improved maintainability.
●​ Conducted code reviews to maintain code standards and best practices.
●​ Integrated third-party SDKs including Adyen and Jumio.
●​ Developed new features from scratch, contributing to the app's core functionality.
●​ Worked as part of a team to define and implement effective solutions.

Andersen Agency
​
Project: RM Toolkit​
Duration: Jun. 2021 - Nov. 2021

Technology Stack: Kotlin, MVVM, Kotlin Coroutines, Realm (for offline mode), Retrofit,
Koin

Description:​
The RM Toolkit is a comprehensive program designed to enhance communication within
a company. It enables scheduling meetings, setting and tracking goals, providing
feedback, and onboarding new employees.

Responsibilities:

●​ Fixed critical bugs to ensure smooth functionality.
●​ Improved UI/UX design for a better user experience.
●​ Tested new features to maintain high-quality standards.
●​ Implemented local storage with the Realm for the offline mode
●​ Integrated the Android Navigation Component for streamlined app navigation.

Freelance
​
Project: Journal​
Duration: May. 2020 - Jun. 2021

Technology Stack: Kotlin, Java, Kotlin Coroutines, MVP, Retrofit2, SQLite (Room),
Dagger (Hilt).

Description:​
The Five Minute Journal app leverages principles of positive psychology to enhance
happiness in just five minutes a day. It focuses on self-care, mental health, and
motivation, featuring tools such as a gratitude journal, positive affirmations, and a mood
tracker to foster stress-free self-improvement and mindfulness.

Responsibilities:

●​ Fixed critical bugs, enhancing app stability from 75% to 98% (Crashlytics report).
●​ Addressed and resolved user-reported issues.
●​ Improved UI/UX design for better user experience.
●​ Conducted unit testing to ensure code quality and reliability.
●​ Implemented a dark theme to provide a better visual experience in low-light
environments.
●​ Added localization support for four languages, broadening the app's user base.
●​ Integrated video and image editing capabilities using the P.E Android SDK.
●​ Worked with ExoPlayer2 for advanced media playback.

Education
1. 2014-2016
Bachelor of Science - Enterprise Economics
Odessa National Academy of Food Technologies

2. 2011-2014
Specialist of Science - Enterprise Economics
Odessa College of Computer Technologies Honours degree.

Qualifications
1. May 2021; Andersen — Android Courses
2. October 2017; Personal Search Engine Optimization Certificate by Uprofs
3. September 2017; Google Analytics Individual Qualification
4. December 2014 — July 2015; Internet Marketing courses at the “IT STEP” School,
Odesa, Ukraine
5. HTML & CSS by htmlacademy

Languages
1. English – Upper-Intermediate
2. Ukrainian – Native