Aleksander Kowalczyk, Developer in Katowice, Poland
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Aleksander Kowalczyk

Verified Expert  in Engineering

Software Developer

Katowice, Poland
Toptal Member Since
December 6, 2014

Aleksander is a senior .NET developer with experience in software architecture design and analysis, project management, and team leadership. Thanks to the variety of industry sectors and roles in his background, he has the ability to learn quickly and to manage unexpected obstacles.


Munu AS
ASP.NET Core, .NET, C#, TypeScript, React, Redux, Xamarin...
RetailPOS (Toptal Client)
ASP.NET Core, C#, .NET, Xamarin, Universal Windows Platform (UWP), .NET Core...
Meeteor, LLC (Toptal Client)
TypeScript, JavaScript, Node.js, React, Ruby on Rails (RoR), C#, .NET, .NET Core




Preferred Environment

TFS, Subversion (SVN), Git, WebStorm, Visual Studio, .NET Core, React

The most amazing...

...thing I've created is a framework for rapid development of line-of-business applications.

Work Experience

Senior Full-Stack Developer

2017 - 2018
Munu AS
  • Developed a QR-based self-service app for F&B/HoReCa.
  • Created a modern POS system working offline and online, synchronized with self-service ordering.
  • Started the process of growing the development team by hiring senior developers.
  • Introducing product development processes, from ideation to delivery.
  • Mobile app for waiters for a quick and efficient ordering process.
Technologies: ASP.NET Core, .NET, C#, TypeScript, React, Redux, Xamarin, Universal Windows Platform (UWP), JavaScript, .NET Core

Senior Full-stack Developer

2016 - 2017
RetailPOS (Toptal Client)
  • Wrote the main POS app for a touch-based POS device.
  • Created a small POS app for Android phones and tablets.
  • Developed the TableApp for customer self-service for Android tablets.
  • Integrated all of the above with various peripherals like bank terminals, weights, displays, bard code, QR scanners, etc.
  • Created a service for communication between the apps.
Technologies: ASP.NET Core, C#, .NET, Xamarin, Universal Windows Platform (UWP), .NET Core, React

Senior Full-stack Developer

2015 - 2017
Meeteor, LLC (Toptal Client)
  • Integrated Google Calendar using the Google Calendar API in the back-end using Ruby on Rails and creating a Google Chrome Extension for the front-end.
  • Integrated Outlook Desktop for PC (2010-2016 versions) with a custom Outlook COM add-in.
  • Integrated Office 365 in the scope of Outlook web and desktop, 2016 Windows and Mac, with a custom office app.
  • Integrated Atlassian HipChat using React in the front end and Node.js in the back end.
Technologies: TypeScript, JavaScript, Node.js, React, Ruby on Rails (RoR), C#, .NET, .NET Core

Senior .NET Developer

2014 - 2015
iQuest, LLC
  • Created the architecture for a public-facing, cloud-based web application using Onion Architecture and domain-driven design.
  • Implemented the foundations of the web application back-end tier using WebAPI in the newest ASP.NET 5 version.
  • Implemented the foundation of the web application front-end tier using ASP.NET 5 and AngularJS.
  • Trained co-workers in ASP.NET 5 to participate in the development of the major web app of the platform.
  • Consulted on technical matters with the founders on the technical possibilities in the scope of app development.
  • Provided time estimations and project management support.
Technologies: AngularJS, Azure Websites, Azure Table Storage, Azure DocumentDB, ASP.NET MVC 6, ASP.NET MVC 5, .NET, .NET Core, React

Senior .NET Developer and Technical Lead

2014 - 2014
OpenSky Data Systems
  • Created a mobile Tablet PC Windows 8.1 application with user-friendly touch support that provides a unified approach for medical staff to conduct clinical assessments for home and acute care of elderly patients.
  • Created a library that fixes bugs in touch support WPF and adds support to the Win8 touch keyboard.
  • Analyzed technical solutions as the tech lead and suggested the most appropriate ones for provided expected functionalities.
  • Consulted with project managers on development processes, timing, and approaches, as well as UI/UX design.
  • Discussed possible reasons for issues and ways to analyze them more deeply with QA to provide better feedback for developers.
  • Trained developers in WPF, MVVM, and best practices in developing Windows desktop applications with touch support.
  • Projected the whole structure of the solution on the client-side.
  • Implemented the projected solution in collaboration with the development team.
Technologies: Entity Framework, Windows Communication Foundation (WCF), Model View ViewModel (MVVM), Windows Presentation Foundation (WPF), .NET, SQL

Senior .NET Developer and IT Manager

2013 - 2014
KOBA Systems
  • Created a sales system designed to support ticket sales for transportation companies, with potential for sophisticated generation of preconfigured sales reports and statistics on demand by the end-user.
  • Developed a project management system for accounting companies.
  • Built and maintained the front-end software for ticket machines and ticket POS.
  • Conducted business analysis for a dedicated rehabilitation hospital system.
  • Served as the project manager and team leader in the development process on the first pilot phase for a dedicated system for a rehabilitation hospital.
Technologies: Microsoft SQL Server, Model View ViewModel (MVVM), Managed Extensibility Framework (MEF), Entity Framework, Windows Communication Foundation (WCF), Windows Presentation Foundation (WPF), C#, .NET, SQL

Senior .NET Developer and IT Manager

2012 - 2013
  • Recruited developers and IT specialists and established an IT department.
  • Managed the newly-established IT department consisting of .NET developers, testers, support, and implementation specialists.
  • Created an MS SQL/WCF-based back-end for 32 ticket machines selling tickets of the Silesian Railways.
  • Built an MS SQL/WCF back-end and a Windows embedded front-end client application that allows for the sale of Silesian Railway tickets by various sales agents such as small shops. The sales system was used by 60 sales agents.
  • Created a server component that receives data from GPS Trackers mounted in 72 trains via TCP/IP signals and a web application that allows for following actual train positions and routes.
Technologies: .NET Compact, Microsoft SQL Server, jQuery, ASP.NET MVC, Entity Framework, Windows Communication Foundation (WCF), Windows Presentation Foundation (WPF), C#, .NET, SQL

Senior .NET Developer | Project Manager

2011 - 2012
  • Programmed the Windows Client part of a dedicated product management system in WPF.
  • Created add-ins to CAD Application Solidworks and invented integration for them with the product management system.
  • Developed add-ins to MS Outlook, MS Excel, and MS Word, integrating them with the product management system.
  • Trained developers in the scope of WPF application development.
  • Led the team and managed projects to implement the product management system for a pilot customer.
  • Conceptualized new functionalities of the PDM such as CAD applications integration, MS Office integration, and CRM.
Technologies: Microsoft SQL Server, JavaScript, jQuery, Ajax, Visual Basic 6 (VB6), COM+, Windows Communication Foundation (WCF), Windows Presentation Foundation (WPF), ASP.NET, C#, .NET, SQL

Senior .NET Developer and Team Leader

2007 - 2011
Logotec Engineering S.A
  • Migrated big CRM and DMS systems from ASP/VB6 to .NET.
  • Consulted with implementation specialists and bigger end customers (>100 users) about expected new functionalities.
  • Created a local client for Windows (WPF/WCF) that integrates the DMS-managed documents with the Windows File Explorer through the context menu and a tray application.
  • Built an add-on to Microsoft Outlook that integrates the mail messages and appointments with a CRM system.
  • Integrated the DMS system with MS Dynamics CRM solution.
  • Designed a completely new front-end for big DMS and CRM systems in ASP.NET/Ajax.
  • Developed a mobile version of the CRM system for Windows Mobile devices.
  • Implemented several new functionalities in the DMS and CRM systems.
Technologies: Microsoft SQL Server, HTML, CSS, JavaScript, Ajax, Visual Basic 6 (VB6), COM+, Web Services, ASP.NET, VB.NET, C#, .NET, SQL

.NET Developer

2009 - 2010
  • Developed a backup tool that watches several directories with MFT/USN Journal and copy-blocked files using Volume Shadow Copy Service.
  • Built a dedicated mobile CRM application running on Windows CE.
  • Designed and developed an analysis tool for card games.
  • Conceptualized and created a highly configurable and reusable framework for data management applications.
  • Consulted on the scope of software development and architecture.
Technologies: Windows Mobile, MSSQLCE, Windows Forms (WinForms), C#, C++/CLI, .NET, SQL, React

.NET Developer

2006 - 2007
MiComp Computer Systems
  • Created an add-on to Microsoft Outlook, allowing full synchronization of mail, appointments, and tasks with a web-based document management system.
  • Designed WYSIWYG-based workflow diagrams for the document management system on a WinForms embedded control in an ASP.NET WebForms application.
  • Built a drag-n-drop file upload on a web-based system with the help of embedded WinForms controls.
  • Wrote data archiving functionality in a document management system written in ASP.NET WebForms.
  • Fixed bugs in the document management system (ASP.NET WebForms).
Technologies: Web Services, Windows Forms (WinForms), Microsoft SQL Server, ASP.NET Web Forms, C++/CLI, C#, .NET, SQL

Junior PHP Developer

2006 - 2007
MMG Marketing Management Group
  • Created a highly customizable content management system.
  • Built various websites, particularly online shops.
  • Designed databases in MySQL for online shop websites.
  • Fixed errors in PHP, JavaScript, MySQL on existing websites created by former employees.
  • Designed the UI/graphics for various eCommerce websites.
Technologies: MySQL, JavaScript, CSS, HTML, PHP, SQL

A7 EBusiness Platform

A line-of-business system platform which I created as a proof-of-concept when working on similar systems, to check what can be done better.


Notes app where the simplicity of creating and organizing notes is the top priority. 90% of the site is for your notes, keeping anything distracting from the notes to the minimum. To categorize, just type a #hashtag to your note, and you have created a main category of notes. Add to it a dot sign - that will create a #hierarchic.hashtag - putting your note into subcategories.

A7 DocumentDb Studio

A7 DocumentDb Studio is a tool to make it easier to explore the databases in the Azure NoSQL DocumentDB database. It allows filtering data based on a UI-based generator, and to edit SQL by hand.

A7 JsonViewer

Simple and lightweight JSON viewer and editor for Windows.

A7 SqlTools

SQL tools for comparing, searching, and exploring data in a MS SQL database.
2004 - 2008

Bachelor's Degree in Computer Science and Computer Networks

University of Silesia - Katowice, Poland


React, Node.js, jQuery, Task Parallel Library (TPL), Managed Extensibility Framework (MEF), Windows Forms (WinForms), Entity Framework, Facebook API, OpenStreetMap API


Visual Studio .NET, SOLIDWORKS, Visual Studio, WebStorm, Git, Subversion (SVN), TFS


.NET Core, ASP.NET Core, ASP.NET MVC 6, Windows Presentation Foundation (WPF), .NET, ASP.NET Web API, CSLA, Swagger, ASP.NET MVC, AngularJS, ASP.NET, Entity, ASP.NET Web Forms, .NET Compact, ASP.NET MVC 5, Ruby on Rails (RoR), Redux


TypeScript, JavaScript, C#, XAML, T-SQL (Transact-SQL), SQL, HTML, HTML5, PHP, CSS, C++/CLI, VB.NET, Visual Basic 6 (VB6), CSS3


Design Patterns, Model View ViewModel (MVVM), Test-driven Development (TDD), Service-oriented Architecture (SOA), UX Design, Model View Controller (MVC), UI Design, Plugin-Based Architecture, COM+, Agile Software Development


Universal Windows Platform (UWP), Xamarin, Azure, Meteor, Windows, Windows Server, Windows Mobile


Microsoft SQL Server, NoSQL, Azure Blobs, Azure Queue Storage, MongoDB, MSSQLCE, MySQL, Azure DocumentDB, Azure Table Storage, Azure Websites, PostgreSQL


Freelancing, Windows Communication Foundation (WCF), Single-page Applications (SPA), DocumentDB, Web Services, Ajax

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