Konstanty Orzeszko, Developer in Warsaw, Poland
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Konstanty Orzeszko

Verified Expert  in Engineering

Full-stack Developer

Warsaw, Poland

Toptal member since December 11, 2021

Expertise
Full-stackFront-endC#.NETJiraXamarinAndroidiOSFlutterDevOpsPostgreSQLAdobe Software Development
Bio

Konstanty is a .NET enthusiast with experience in various mobile, C#, and XAML environments. As an expert in software development and architecture, he understands that clean code and a good foundation are essential. With his systems administration knowledge and console scripting, he created CI/CD pipelines for many projects. Konstanty uses behavior-driven development and domain-driven design to significantly improve stakeholders' satisfaction with the developed product.

Portfolio

PLATONIC Tech UG
Flutter, C#.NET, Mobile, Mobile Apps, APIs, REST, Firebase, Firebase iOS SDK...
Polish Security Printing Works
ASP.NET MVC, Behavior-driven Development (BDD), Test-driven Development (TDD)...
Jacob Levitt
Flutter, Dart, Full-stack, Mobile, Mobile Apps, Android, iOS, APIs

Experience

  • C# - 9 years
  • XAML - 6 years
  • Windows Presentation Foundation (WPF) - 6 years
  • Xamarin - 5 years
  • PostgreSQL - 5 years
  • ASP.NET MVC - 4 years
  • Entity Framework Core - 3 years
  • Behavior-driven Development (BDD) - 2 years

Availability

Part-time

Preferred Environment

PostgreSQL, Xamarin, Windows Presentation Foundation (WPF), ASP.NET MVC, Behavior-driven Development (BDD), DevOps, SQL, Python, Flutter

The most amazing...

...thing I've developed is the eDO App ranked #7 as the productivity app in App Store that utilizes NFC to read data from the Polish ID.

Work Experience

Full-stack Flutter and .NET Developer

2023 - PRESENT
PLATONIC Tech UG
  • Fixed bugs from previous versions of the application.
  • Revamped the mobile UI entirely based on Figma prototypes.
  • Automated the CI/CD of the Azure back end and both Android and iOS applications.
  • Reduced server response times in critical places by a factor of 20.
Technologies: Flutter, C#.NET, Mobile, Mobile Apps, APIs, REST, Firebase, Firebase iOS SDK, Firebase Analytics, Cloud Firestore, Fastlane, Facebook SDK, Google Sign-in, Single Sign-on (SSO), Azure Table Storage, Azure Websites, Azure SQL, Azure Blob Storage API, Android, iOS, MVC Design

Lead ASP.NET Developer

2020 - PRESENT
Polish Security Printing Works
  • Developed the OAuth 2.0-based back-end for identity management and personal data sharing.
  • Facilitated the online event stormings via Miro. Documented results and supervised development.
  • Designed and supervised the usage of strict project architecture.
  • Collaborated with the DevOps team on Kubernetes deployment on the on-premise cloud.
  • Created multiple test suites to mimic partner integrations with Azure Web Apps, Azure Static Web Apps with Blazor WebAssembly (WASM), and Azure Functions with C#.
Technologies: ASP.NET MVC, Behavior-driven Development (BDD), Test-driven Development (TDD), Domain-driven Design (DDD), Kubernetes, Docker, PostgreSQL, Marten, Azure Functions, Azure Websites, Blazor, Technical Hiring, Code Review, Source Code Review, Interviewing, Task Analysis, Back-end, ASP.NET Core, Azure, Full-stack, Front-end, Google Cloud Platform (GCP), Architecture, Leadership, Desktop Web Design, C#.NET

Flutter Developer

2022 - 2023
Jacob Levitt
  • Developed new functionalities based on saving application states between loads.
  • Moved the back end from a slow WordPress solution to a blazingly fast CDN server. Optimized the costs of serving high-quality photos.
  • Helped in the process of transferring ownership on both the Play Store and App Store. Also launched new versions of the apps.
Technologies: Flutter, Dart, Full-stack, Mobile, Mobile Apps, Android, iOS, APIs

Developer Screener

2022 - 2022
Toptal
  • Achieved a higher than usual satisfactory rate of interviewed rejected developers, thanks to my soft skills.
  • Trained new screeners by either letting them shadow my calls or by coworking background checks on candidates.
  • Engaged in recruitment processes of over 230 candidates, performing code reviews and checking architectural knowledge and soft skills.
Technologies: JavaScript, C#, React, Dart, Flutter, Windows Desktop

Xamarin Team Leader

2017 - 2020
Polish Security Printing Works
  • Created, led, and managed a team of three Xamarin developers, one back-end developer, two testers, and one analyst. I delivered every project on time.
  • Followed the Scrum methodology, facilitated planning, presented every increment during sprint reviews, and handled stakeholder interactions.
  • Implemented the screens and flows designed by GFX and UX teams via Adobe XD.
  • Created and maintained the CI/CD pipeline, including running unit tests on mobiles, local automated UI testing, UI testing on AppCenter cloud farm, and deployment on multiple testing groups and respective stores.
Technologies: ASP.NET MVC, Xamarin.Forms, Xamarin.iOS, Xamarin.Android, Adobe Experience Design (XD), Blockchain, PostgreSQL, Scrum, Visual Studio App Center, DevOps, GitLab CI/CD, Observer Pattern, Code Review, Task Analysis, Technical Hiring, Interviewing, Source Code Review, Android, iOS, Mobile Apps, Firebase, Cloud Firestore, Leadership, Requirements Analysis, Software Design, Architecture, C#.NET

.NET Developer

2015 - 2017
Polish Security Printing Works (PWPW)
  • Participated in developing the ERP system designed to handle the Polish ID production cycle comprehensively. The modules included ID ordering, document engraving, CR and QA, document shipping, and logistics.
  • Used Jira as a task management system for developing new functionalities and bug fixing.
  • Developed the custom-tailored CI/CD pipelines for a complex system deployed at restricted access areas without internet connectivity.
Technologies: Windows Presentation Foundation (WPF), DevExpress Controls, Oracle SQL, C#, Waterfall Methodology, Jira, XAML, Model View ViewModel (MVVM), Observer Pattern, Microsoft SQL Server, Desktop App Development, Desktop, C#.NET

Experience

eDO App

https://apps.apple.com/pl/app/edo-app/id1503023855?l=pl
The eDO app is an application that allows users to confirm their identity and create an electronic signature securely. It is a Xamarin native mobile application for iOS and Android, providing the requesting parties with personal information stored on a Polish passport and ID. The application utilizes NFC to access data, while back-end services provide data to the connected partners via OAuth 2.0.

I was the lead back-end developer and participated in the architecture and design of mobile applications.

Mobile Big Family Card

https://www.gov.pl/web/mobywatel/karta-duzej-rodziny-mkdr
I was the team leader for the first government-accepted digital document in Poland. The application provided users with access to proof of enrollment in the government benefits program and the ability to navigate to the nearest partners of the program. The app is written in Xamarin Forms for Android and iOS.

Polish ID Personalization System (SPD)

A .NET ERP system designed to comprehensively handle the Polish ID production cycle. Modules included ID ordering, document engraving, document CR and QA, and document shipping and logistics. The project took two years to complete. I began as a regular developer and finished as a senior overseeing both web API back end and front end in WPF.

Kontroler | Flutter App with IoC Communication

The Flutter app communicated with temperature and humidity sensors located at the production site via the BLE protocol.

The application's main objective was to monitor crucial parts of the factory line, which are hard and time-consuming to do by hand.

KASA | Desktop Application Communicating with Credit Card Terminals

A C# WPF front-end application communicating over REST framework with ASP.NET Web API. The server is managed and proxied TCP communication with multiple card terminals over clients' networks via SignalR.

The solution was installed over numerous government offices, allowing them to accept card payments.

Educational App for Medical Professionals

A Flutter-based app designed to help medical professionals identify dermatology issues. I was hired as a developer to fix a few issues and implement state persistence. During the engagement, I identified a bottleneck in the form of a slow back end and reimplemented it on a fast CDN and local caching.

Social App for Events

A Flutter app with a .NET back end hosted on Azure. I was the only developer hired to help with the application release. Initially, I fixed a few bugs, then revamped the entire front end based on Figma prototypes. Lastly, I implemented SSO (Google, Apple, and Meta) and increased the speed of most critical endpoints.

Education

2012 - 2016

Engineer's Degree in Computer Science

Polish-Japanese Academy of Information Technology - Warsaw, Poland

Skills

Libraries/APIs

Xamarin.iOS, Xamarin.Android, React, Web API, Firebase iOS SDK, Facebook SDK, Azure Blob Storage API

Tools

Jira, Visual Studio App Center, Adobe Experience Design (XD), GitLab CI/CD, Firebase Analytics, Fastlane

Languages

C#, XAML, C#.NET, SQL, Python, JavaScript, Dart

Frameworks

Windows Presentation Foundation (WPF), Entity Framework Core, ASP.NET MVC, .NET Core, .NET, ASP.NET Core, Flutter, Blazor, iOS SDK, Android SDK

Paradigms

Model View ViewModel (MVVM), Mobile Development, Requirements Analysis, Desktop Web Design, Desktop App Development, Behavior-driven Development (BDD), DevOps, Scrum, Test-driven Development (TDD), REST, MVC Design

Platforms

Xamarin, Android, iOS, Desktop, Windows Phone 8, Docker, Azure, Bluetooth Low Energy (LE), Firebase, Blockchain, Kubernetes, Azure Functions, Google Cloud Platform (GCP), Windows Desktop, Mobile

Storage

PostgreSQL, Microsoft SQL Server, Cloud Firestore, Oracle SQL, Azure Websites, Azure Table Storage, Azure SQL

Other

DevExpress Controls, Xamarin.Forms, Code Review, Task Analysis, Technical Hiring, Interviewing, Source Code Review, Back-end, Mobile Apps, Front-end, Full-stack, Full-stack Development, Leadership, Software Design, Architecture, Industrial Internet of Things (IIoT), Internet of Things (IoT), Domain-driven Design (DDD), Waterfall Methodology, Marten, Observer Pattern, Akka.NET, Web Development, DevExpress, TCP/IP, APIs, Google Sign-in, Single Sign-on (SSO)

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