Bartosz Kraszewski, Software Developer in Bialystok, Poland
Bartosz Kraszewski

Software Developer in Bialystok, Poland

Member since August 20, 2019
Bartosz is a software engineer specializing in mobile application development. He focuses on code quality and adherence to standards and has several years of experience working in fast-paced, product-oriented environments, including Silicon Valley startups. Bartosz is also a co-founder of Mobile Bialystock: a local group for mobile technology enthusiasts.
Bartosz is now available for hire




Bialystok, Poland



Preferred Environment

GitKraken, Sublime Text, Android Studio, MacOS

The most amazing...

...thing that I've built was an Android app that recognizes a user's meal from a photo and automatically calculates the calories and other nutrition details.


  • Lead Flutter Developer

    2021 - 2022
    Publicis Sapient
    • Developed a new digital banking app from zero to the production release.
    • Led the team responsible for user registration and customer onboarding.
    • Implemented a custom framework to manage the registration process based on configuration files.
    Technologies: Flutter, Dart, Leadership, Mobile UI, APIs
  • Flutter Expert

    2020 - 2022
    Dropsource (via Toptal)
    • Implemented a high-quality, cross-platform application in Flutter.
    • Designed and implemented a data model stored in Firebase.
    • Used an innovative tool in Flutter development: a library called Monarch.
    Technologies: Dart, Firebase, Flutter, Mobile UX
  • Senior Android Developer

    2019 - 2021
    Remojo (via Toptal)
    • Designed, developed, and published a porn blocking app.
    • Provided training and helped after the project was in the maintenance stage.
    • Launched the app from the idea through the PoC to the production app.
    • Implemented AI-based service, detecting pornography on the user screen.
    • Designed and implemented both client and cloud-side subscription payment systems integrated with Google Play APIs.
    Technologies: SDKs, Model View Viewmodel (MVVM), Kotlin, Android
  • Android Tech Lead

    2016 - 2021
    • Worked as an Android team leader in a distributed remote team—developing complex fitness/personal health applications with multiple versions. Responsible for planning, developing, refactoring, and also mentoring team members.
    • Added new features to a complex codebase, including Kotlin support, introducing the multi-module architecture, delivering the MVP, and later implementing an MVVM approach and data binding.
    • Optimized a customer app that reduced startup time and retrieved tons of lost animation frames. Profiled and analyzed the app's network performance with the AT&T Video Optimizer.
    • Refactored user-profile-related classes to use repository pattern—introducing a local cache and lazy sync mechanism using WorkManager.
    • Designed the initial Android app boilerplate used for new projects, implementing the necessary configuration dependency injection, and ensuring it has common utilities and is unit test friendly. The project was open-sourced as a starter app.
    • Worked as a tech lead of the Android department, responsible for recruitment, helping the sales team, and estimating and analyzing projects.
    • Led a Flutter project for a Polish betting company; also designed and developed Android and iOS applications handling account verification, betting, and payments.
    Technologies: Java, Kotlin, Android, Flutter
  • Senior Android Developer

    2015 - 2016
    • Implemented an emoji system before the EmojiCompact library was made public.
    • Refactored a photo-stream module by introducing a new architecture and interfaces to reduce dependencies and simplify the codebase.
    • Implemented the UI and backing logic for private and public groups.
    • Optimized, implemented the new architecture, and reskinned all authorization and onboarding screens.
    • Developed an internal framework for annotation-based widget coloring that was more maintainable than Android styles and could be updated in runtime.
    Technologies: Java, Android
  • Co-founder | Lead Developer

    2013 - 2016
    • Designed a multi-platform, complex data model of chemical compounds (SQLite).
    • Created a native Android and iOS app (Java, Objective-C).
    • Developed several types of utility software to facilitate database management (Java FX and Node.js).
    • Created a marketing-and-user-acquisition strategy.
    • Built mini-games and connected them to Google Play Games Services.
    Technologies: Objective-C, JavaFX, Android, SQL, JavaScript, Kotlin, Java
  • Software Engineer | Team Leader

    2013 - 2015
    • Worked on multiple prototypes in a fast-changing, customer-oriented environment, specifically the US healthcare startup market.
    • Developed a kiosk app for tablets (native Android); built a secure platform for performing patient screening and integrated the connectivity and security systems.
    • Contributed to the build of Tangram Clock (mostly the UI): a native Android app for cognitive impairment screening.
    • Built an internal framework for publishing patients' wellness screenings, written in GWT and Spring.
    • Designed and worked as a part of a team on a web app for annual wellness visits (both the patient and doctor sides).
    Technologies: PostgreSQL, MongoDB, Angular, JavaScript, Android, Spring, Java, GWT
  • Database Developer

    2012 - 2013
    Tower Group
    • Created automated ETL jobs that filled out data warehouse with insurance claim information.
    • Built an automated-reporting service to compare financial data before and after data migrations.
    Technologies: Microsoft SQL Server, SQL
  • Junior Java Developer

    2011 - 2012
    GRC Solutions
    • Designed and implemented a workflow management engine and was responsible for creating custom document acceptance flows.
    • Implemented multiple features in GRC's workflow software which automated the document workflow system.
    • Integrated a type of role-analysis software with SAP which red current user roles from the system and exported it to an internal database.
    Technologies: SAP, Spring, Microsoft SQL Server, CSS, XHTML, JSF, Java


  • [NDA] Exercise Database

    I developed an offline-first exercise database for Android. It allows a user to use ready-to-use workouts (exercises, video workouts) and also create their own.

  • [NDA] Nutrition Manager

    I built an Android app that makes daily nutrition tracking easy. It has a built-in meal database and the ability to generate meal plans and track calories and nutrition details.

  • [NDA] Fitness Tracker

    I developed a complex app allowing the user to track daily activity data including the number of steps, your nutrition, commute time, exercises, heart rate, and quality of sleep.

  • Chemik Android App

    I developed a native Android app for learning chemistry. A user can use the periodic table like a keyboard to check information about elements and compounds. It also has built-in mini-games to learn the periodic table and calculators to solve chemistry tasks.

  • Mewe Android App

    I built an Android application for a privacy-first social network.

  • Tangram Safe

    I built a secure kiosk app that acts as a launch pad for multiple screening applications to be used in hospitals.


  • Frameworks

    Android SDK, JUnit, Flutter, GWT, Spring, Angular, JSF, Dagger 2
  • Libraries/APIs

    Android API, RxJava 2, Node.js
  • Platforms

    Mobile, Android, iOS, MacOS, JavaFX, Firebase
  • Other

    Senior Android, Mobile Architecture, APIs, GitKraken, Software Engineering, Computer Science, Artificial Intelligence (AI), OOP Designs, Leadership, Mobile UI, Mobile UX
  • Languages

    Java, Kotlin, SQL, Objective-C, XHTML, CSS, JavaScript, Dart
  • Tools

    Android Studio
  • Paradigms

    Agile, Model View Viewmodel (MVVM), Mobile Development, Functional Programming
  • Storage

    SQLite, MongoDB, PostgreSQL, Microsoft SQL Server
  • Industry Expertise

    Project Management


  • Master's Degree in Computer Science
    2012 - 2014
    Bialystok Technical University - Białystok, Poland
  • Bachelor of Engineering Degree in Computer Science
    2008 - 2012
    Bialystok Technical University - Białystok, Poland


  • Divide and Conquer, Sorting and Searching, and Randomized Algorithms
    Stanford University via Coursera
  • Associate Android Developer
    JANUARY 2017 - JANUARY 2020

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