Mateusz Grzegorzek, Developer in Wrocław, Poland
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Mateusz Grzegorzek

Verified Expert  in Engineering

Software Developer

Wrocław, Poland
Toptal Member Since
January 7, 2014

Mateusz is an iOS and Windows Phone expert helping companies and startups design and develop mobile apps tailored to user needs. He holds a Master's Degree in Information Technology from the Warsaw University of Technology and has been developing mobile applications since 2004.


The Run SMART Project, LLC
Flutter, ASP.NET, iOS, Android, Dart, Swift, jQuery, .NET, Azure
MoadBus, Inc.
Windows, Windows Phone, iOS
Windows Phone, iOS, .NET, Azure, Dart, Flutter, Swift, Android




Preferred Environment

.NET, Visual Studio, MacOS, Xcode, Visual Studio Code (VS Code), Flutter, .NET Core, Azure, Dart

The most amazing...

...project I've ever created is the platform, a coaching app for runners. I've built both mobile and web apps and maintained the cloud infrastructure.

Work Experience

Lead Developer | Mobile and Web

2014 - PRESENT
The Run SMART Project, LLC
  • Developed iOS and Android mobile apps. Ported the project from a native mobile app to Flutter in 2020.
  • Built the web app, back-end and front-end, and REST APIs.
  • Maintained the cloud infrastructure on Azure which handles 20,000 to 30,000 monthly active users.
Technologies: Flutter, ASP.NET, iOS, Android, Dart, Swift, jQuery, .NET, Azure

Senior iOS/Windows Phone Developer

2009 - PRESENT
MoadBus, Inc.
  • Developed and maintained a mobile banking application for iOS and Windows Phone.
  • Developed a proof of concept app for iPad helping to perform day-to-day tasks for bank clerks.
  • Created several app prototypes for mobile payment, e-coupon, e-wallet, etc.
Technologies: Windows, Windows Phone, iOS

Owner, Freelancer

2006 - PRESENT
  • Developed the YomoMedia News Reader app for the Windows Phone OS.
  • Built several games for the SonicBoom Inc. company for iPhone.
  • Developed an eBook reader app for Windows Phone.
  • Created several apps for the Windows Mobile platform (Gentimer, Friendzee, and Fishopolis).
  • Handled several small projects for other companies, including maintaining existing apps, etc.
Technologies: Windows Phone, iOS, .NET, Azure, Dart, Flutter, Swift, Android

Windows Mobile Developer

2004 - 2006
Psiloc Mobile Solutions
  • Developed and maintained several apps for Windows Mobile (World Traveller, TinyGPS, Wireless Presenter).
Technologies: C++, Windows Mobile

V.O2 is a coaching app for athletes of all levels looking to improve their running. The app comprises web and companion mobile apps and handles about 20,000 to 30,000 monthly active users. I've been a lead developer behind the project.

Mobile Banking App Suite
The Mobile Banking suite consists of several applications for several mobile operation systems:
• Mobile Banking
• Mobile Wallet
• Mobile Branch Banking

The project was created under NDA and I cannot share the details about the contractor, but the link details some general information about the projects.


InstaSize is still the original and easiest way to post entire photos on Instagram without cropping. We’ve just added a few more features that will make your photo’s that much better.

* The app allows to post entire photos on Instagram without cropping
* Photo editing features – filters, overlays, scale, crop, etc.
* Use of multiple Nokia Imaging SDK filters (several custom ones)
* Windows Azure services integration
* Advanced Memory Management – the application requires significant amount of memory during rendering as it can create images up to 2048x2048px size.
* Custom UI Elements - several UI controls and animations had to be created specifically for this app

Port BarTune iOS app to Windows Phone

The Windows Phone app was created from scratch as exact replica of iOS version to give all users the same experience across all platforms (iOS, Windows Phone and Android). Android project involved upgrading existing app to match the UI of 2 other applications and fixings several bugs.

YomoMedia News Reader

YomoMedia is the most complete RSS Newsreader and Podcast Viewer available for Windows Phone 7. It is now updated for Mango background operation and tiles.

Ebook Reader for Windows Phone's eBook Reader lets users read their favorite books on the go. Users can visit and choose from a massive collection of popular books for rapid download or for reading online from any internet-connected device.


C#, Objective-C, Swift, C, C++, Java, Dart


.NET, Cocoa Touch, ASP.NET, Swagger, Flutter, .NET Core, Angular


Object-oriented Programming (OOP), Agile Software Development


iOS, Windows Phone, Windows Phone 7, Windows Phone 8, Android, Windows, Azure, Windows Mobile, MacOS, Visual Studio Code (VS Code)


Financial Software, Software Development, Financial Software Developer, User Experience (UX)


Microsoft Silverlight, Xcode, Visual Studio 2012, Visual Studio 2010, Visual Studio, Visual Studio 2008


Facebook API, jQuery, jQuery UI, CocoaPods


SQL Server 2008, Microsoft SQL Server, Couchbase

2002 - 2007

Master's Degree in Information Technology

Warsaw University of Technology - Warsaw, Poland

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