Damian is available for hire
Hire DamianDamian Chmielewski
Verified Expert in Engineering
C# Developer
Warsaw, Poland
Toptal member since February 18, 2015
Bio
Damian is an enthusiastic ASP.NET and PHP developer with over ten years of experience in professional development, mainly for the banking, transportation and insurance industries. His freelance work includes various technologies, including MS SQL database and front-end layers using JavaScript frameworks such as Angular, React, or Vue.js.
Portfolio
Psychoterapy Office Hygge
AngularJS, Angular, ASP.NET, WordPress SEO, WordPress, .NET, .NET Core...
Micrima Limited
C#, .NET Core, Windows Presentation Foundation (WPF), Databases, MySQL...
Sterlingbuild Ltd
.NET, C#, XML, Git, Model View Controller (MVC), Scrum, MySQL...
Experience
- C# - 10 years
- ASP.NET - 10 years
- ASP.NET MVC 4 - 8 years
- jQuery - 8 years
- Microsoft SQL Server - 7 years
- Razor - 6 years
- AngularJS - 5 years
- Vue - 3 years
Work Experience
Partial CTO, .NET/WordPress/Python Developer
2022 - PRESENT
Psychoterapy Office Hygge
- Led technical teams across marketing, accounting, and IT, ensuring alignment with management and office staff.
- Estimated financial, strategic, and non-financial indicators for proposed projects.
- Developed a WordPress-based landing page for the organization.
- Built a registration system for psychological consultations.
Technologies: AngularJS, Angular, ASP.NET, WordPress SEO, WordPress, .NET, .NET Core, Management, IT Management, Low Code
Full-stack .NET Developer, Lead Architect
2024 - 2024
Micrima Limited
- Built a full API for handling data management with the diagnostics.
- Set up an application in an Azure environment and MySQL.
- Architected a full website based on Blazor to handle the API.
Technologies: C#, .NET Core, Windows Presentation Foundation (WPF), Databases, MySQL, Medical Applications, IEC 62304, Cloud Architecture, Artificial Intelligence (AI), Claude Code, Claude, AI Agents, FastAPI, Engineering Management, C#.NET, Low Code, NetSuite, NetSuite OneWorld, SuiteScript 2, ServiceNow, Discovery, Asset Management, Dashboards, Architecture, Solution Architecture, Technical Architecture, Office 365, Teams, Technical Leadership
C#.NET Expert and Head of IT
2022 - 2024
Sterlingbuild Ltd
- Simplified project complexity through extensive refactoring processes.
- Managed live releases and configured deployment pipelines.
- Completed a full server migration with customized configuration refactoring.
- Delivered new features aligned with company goals.
- Facilitated communication between clients and developers to address mutual needs.
Technologies: .NET, C#, XML, Git, Model View Controller (MVC), Scrum, MySQL, Microsoft SQL Server, JSON, JavaScript, CSS, HTML5, Bootstrap, Bootstrap 5, Artificial Intelligence (AI), Claude Code, Claude, AI Agents, FastAPI, Engineering Management, C#.NET, Finance, ServiceNow, Discovery, Asset Management, Dashboards, Architecture, Solution Architecture, Technical Architecture, Office 365, SharePoint, Teams, Technical Leadership
Full-stack .NET Developer and Project Manager
2020 - 2022
looking4
- Managed and stabilized old ASP.NET solutions for car parking reservation systems while building new solutions based on the latest AWS event bus and .NET Core API.
- Implemented new functionalities and fixed existing bugs.
- Managed and developed AWS DevOps deployment lifecycle.
- Handled the logic for adding custom screens in the REST API.
- Built integrations between multiple APIs for booking and payments.
Technologies: Entity Framework, Entity Framework Core, .NET Core, ASP.NET, APIs, Amazon Web Services (AWS), EventBus, Full-stack, Front-end, CSS, Databases, Scrum, Engineering Management, C#.NET, ServiceNow, Discovery, Asset Management, Dashboards, Architecture, Solution Architecture, Technical Architecture, Office 365, SharePoint, Teams, Technical Leadership
Full-stack Developer
2020 - 2020
WSL Consulting
- Rebuilt UI components.
- Added a new Vue component.
- Handled graphs and charts in the UI.
- Adjusted styles according to designers' descriptions.
- Fixed and optimized the back end.
Technologies: Chartist.js, Vue, ASP.NET, Full-stack, Front-end, Databases, Scrum, Finance, Teams, Technical Leadership
Owner
2019 - 2020
DCH Roots
- Built a monitoring system for hospital procedures.
- Managed the board UI based on Vue.js.
- Built a .NET Core back-office REST API.
- Developed a Node.js-based solution handling IoT.
- Utilized VueSax as the main UI framework.
- Built a PHP management UI.
- Used Laravel for PHP maintenance.
- Managed the UI of a site database hosted on MySQL.
Technologies: LiteDB, Entity Framework, Vue, Node.js, SignalR, .NET Core, Full-stack, Front-end, Databases
Full-stack Developer and Lead Developer
2019 - 2020
Shields CG
- Built a REST API for a card game system.
- Built hub infrastructure for SignalR messaging.
- Built a test API for a card game in Vue.js.
- Added new components in Vue.js.
- Used Vuesax as a UI library.
- Added a LiteDB-based database.
Technologies: React, LiteDB, SignalR, Vue, .NET Core, Full-stack, Front-end, CSS
.NET Developer
2019 - 2019
Wound Zoom
- Built an app for highly specialized medical teams.
- Refactored the old structure of two main sections from MVC to Angular.
- Migrated data context from obsolete Hibernate into the latest version of Entity framework.
- Vastly improved app performance.
Technologies: Entity Framework, Entity Framework Core, Angular, React Native, .NET, Full-stack, Front-end, Databases, Scrum
Lead Full-stack .NET Developer
2017 - 2019
Wealth c.o.
- Prepared a web project to maintain a large amount of financial information.
- Built a PDF and CSV parser to collect transaction information.
- Created a MVC .NET application for end-user use.
- Developed a WPF application for administration purposes.
- Set full CI based on Bitbucket and Azure, setting up Redmine as well.
Technologies: React, Windows Presentation Foundation (WPF), Angular, .NET, Model View Controller (MVC), Full-stack, Front-end, CSS, Databases, Scrum, Finance
Full-stack .NET Developer
2017 - 2017
Illucian, LLC
- Built a React and AngularJS-based front end.
- Developed an auction portal for a big company.
- Created a SignalR-based real-time experience.
- Managed deployment workflow.
- Utilized Entity framework.
Technologies: React, Angular, .NET, Full-stack, Front-end, CSS
Full-stack Developer
2016 - 2017
Arex Pharma
- Prepared a REST API for internal and external purposes.
- Developed code based on business logic.
- Created Selenium and unit tests.
- Created a generic way of importing files with transportation data.
- Built an application based on MVC4 and Razor.
Technologies: REST APIs, SignalR, Model View Controller (MVC), .NET, Full-stack, Front-end, Databases, Finance
Back-end Developer
2015 - 2016
Focust Apps
- Created a back-end Windows service for uploading SQL Reporting Service into blob storage in Azure.
- Built a WCF server handling communication with the database.
- Imported a service for uploading CSV files from Azure Blob Storage to application memory. The generic application is based on reflection.
- Created a rerating tool for calculating best shipment prices based on Azure WebJob.
- Analyzed, refactored, and tested products.
Technologies: SQL Server Reporting Services (SSRS), Microsoft SQL Server, Azure, .NET, C#, Full-stack, Front-end, CSS, Databases
.NET Developer
2015 - 2015
Compu Game
- Worked with Scrum and Mercurial.
- Created a framework for handling a large number of services on distributed machines.
- Implemented the back end for a service bus pattern.
- Worked with Angular on the front end.
- Maintained unit test-driven development.
Technologies: Enterprise Service Bus (ESB), Angular, Mercurial, .NET, Full-stack, Front-end
.NET Developer
2015 - 2015
LuxMed
- Developed a data layer based on ADO, Entity, and Code First.
- Created a front end based on Ext.js.
- Extended and created new JavaScript methods.
- Created a back-end layer based on business requirements.
- Led short training sessions on TDD and BDD with SpecFlow.
Technologies: Ext JS, ASP.NET MVC, Full-stack, Front-end
Full-stack Developer
2015 - 2015
Discover FLA (via Toptal)
- Extended the data layer using Entity framework.
- Added new front-end functionalities.
- Modified the existing architecture to provide the latest .NET features.
- Implemented manual tests and JavaScript tests.
- Created a RESTful application.
Technologies: Git, Entity, ASP.NET MVC, Full-stack, Front-end, CSS, Databases
.NET Developer, Team Leader
2013 - 2015
Cube ITG
- Created a large application for a financial company developed using MVC4.
- Performed multiple operations based on lease agreements, credits, etc.
- Developed a front end based on Knockout.js and some jQuery.
- Created the database layer based on a native repository pattern.
- Led a four-person team analyzing business documentation and creating technical documentation. Assigned tasks.
Technologies: Model View Controller (MVC), Knockout (Knockout.js), jQuery, Razor, ASP.NET, Full-stack, Front-end
.NET Developer
2012 - 2014
Fortress GB
- Developed multiple applications to maintain stadiums.
- Wrote applications in Web Forms, MVC3, and Windows Forms.
- Implemented each app as a single-page application using jQuery and Ajax.
- Developed a small application on tablets for waitresses to sell food and drinks.
- Worked on an MS SQL database. Created tables, procedures, functions, and indexes.
Technologies: Ajax, jQuery, Web Forms, Telerik WebForms Controls, ASP.NET, Full-stack, Front-end
.NET Developer
2011 - 2012
PKO BP
- Created back-end applications for HR.
- Implemented single-page applications based on jQuery and Ajax.
- Created a testing platform. Performed load tests using Visual Studio tools.
- Assisted during deployment on the production servers.
- Provided support for critical cases.
Technologies: Microsoft SQL Server, Model View Controller (MVC), jQuery, ASP.NET, Full-stack, Front-end
Experience
Gym Advisor
An online application for trainers and clients to stay in contact with each other. Extended blog features allow trainers to share their experiences with others. Clients can schedule training sessions with trainers and buy other things connected to training. The application was written in ASP.NET, using MVC4 technology and AngularJS.
Automatic Door Opener
A complete solution for a small office rental. I was a full-stack developer working on hardware based on Raspberry Pi and coding logic in Python. Raspberry was contacting IoT devices for various behaviors and monitoring. I built the API in .Net Core hosted on Azure and front-end in Vue.js for small management.
Education
2023 - 2024
Bachelor's Degree in Marketing and management
Kozminski University - Warsaw
2013 - 2015
Master's Degree in Automation and Robotics
Wroclaw University of Technology - Wroclaw
2007 - 2010
Engineering Degree in Robotics and Automated Control Systems
Wroclaw University of Technology - Wrocław, Poland
Skills
Libraries/APIs
SignalR, jQuery, jQuery UI, Vue, Node.js, React, REST APIs, Entity Framework, Chartist.js
Tools
Subversion (SVN), TFS, Git, Visual Studio 2015, Mercurial, Visual Studio 2013, Visual Studio 2012, LINQ to SQL, Claude Code, Claude, Microsoft Power BI, RabbitMQ, Microsoft Access, Visual Studio, SourceTree
Languages
JavaScript, C#, HTML, CSS, C#.NET, TypeScript, Transact-SQL (T-SQL), SQL, PHP, SuiteScript 2, Python, XML, HTML5
Frameworks
Angular, ASP.NET MVC 4, AngularJS, ASP.NET, ASP.NET MVC 3, Bootstrap, .NET, .NET Core, ASP.NET Core, Razor, SpecFlow, Angular Material, Laravel, Knockout (Knockout.js), ASP.NET MVC, Entity, Windows Presentation Foundation (WPF), React Native, Entity Framework Core, Ext JS
Paradigms
Scrum, Test-driven Development (TDD), REST, Behavior-driven Development (BDD), Model View Controller (MVC), Azure DevOps, Automation, Management, Microservices
Platforms
Azure, Windows Phone 10, SharePoint, Raspberry Pi, Visual Studio Code (VS Code), Amazon Web Services (AWS), WordPress
Storage
Azure SQL, Databases, Microsoft SQL Server, SQL Server 2014, MySQL, Web Forms, SQL Server Reporting Services (SSRS), LiteDB, Oracle 11g, JSON
Other
APIs, Front-end, GitFlow, Full-stack, Artificial Intelligence (AI), AI Agents, FastAPI, Engineering Management, Low Code, Finance, NetSuite, Asset Management, Architecture, Solution Architecture, Technical Architecture, Leadership, NetSuite OneWorld, ServiceNow, Discovery, Dashboards, Office 365, Teams, Technical Leadership, Games, Telerik WebForms Controls, Ajax, Enterprise Service Bus (ESB), Laragon, Software, Software QA, Machine Learning, Robotics, EventBus, Market Risk, Market Demand, IT Projects, Bootstrap 5, Medical Applications, IEC 62304, Cloud Architecture, WordPress SEO, IT Management
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