Consultant, Developer
2005 - PRESENTFreelance- Built a ticket management system for events.
- Created numerous company and product websites and applications.
- Joined existing teams to temporarily boost productivity.
- Designed and implemented a CRM with automation capabilities.
- Acted as an external auditor reviewing quality, robustness, and security.
Technologies: Python, PHP, JavaScript, TypeScript, T-SQL, WordPress, UmbracoDeveloper
2016 - 2018ZampleBox- Worked as a core developer on the main eCommerce product.
- Helped drive the development of new core business features.
- Migrated the application from ASP.NET MVC 5 to ASP.NET Core.
Technologies: ASP.NET Core, AngularJS, SQLServer, AzureTech Lead
2015 - 2017WeTrada- Set up a brand new unique online shopping portal.
- Automated a shopping experience that offers customized communication flows.
Technologies: .NET, AzureFounding CTO
2013 - 2016Postvid, Ltd.- Built a highly scalable back-end service for uploading, handling, converting, and composing user media (photos, videos, and audio).
- Created a web application for creating a fully customized video greeting card.
- Created a full-stack order pipeline service for order and payment tracking with full QOS reporting and alerting.
- Established the technical vision and led all aspects of IT-related development.
- Conducted research and case studies on cutting-edge technologies.
Technologies: C#, DurandalJS, AzureAPI Developer
2015 - 2015Litmus (via Toptal)- Created a high performance API with synchronization capabilities for external services.
Technologies: .NET, AWS.NET Developer
2015 - 2015hopIN (via Toptal)- Migrated over an existing software solution to a more efficient hosting plan on Azure.
- Solved a number of issues with the application.
Technologies: .NET, AzurePHP Developer
2015 - 2015Bumptext (via Toptal)- Solved numerous issues with the existing software solution.
- Proposed a path forward.
Technologies: PHP, XAMPPAzure Expert
2015 - 2015Silec (via Toptal)- Helped to create a deployment strategy for hosting the in-house web application on Azure.
Technologies: Azure, .NETConsultant, Developer
2011 - 2015Web Power- Served as product owner and architect for a major new email marketing product.
- Developed and implemented various web applications and integration solutions for numerous clients.
- Worked as lead architect on an experimental new back-end system for handling all data transactions for the entire product family.
- Consulted both internally and externally on various IT-related topics.
- Handled developer training for clean and testable code with state of the art technologies and practices.
Technologies: PHP, MySQL, JavaScriptLead Developer
2006 - 2011Infocaster- Created services for mass news profiling and analytics.
- Built a recommendation system matching users based on online behavior, suggesting contacts and sources.
- Created online web portals for displaying and managing news (similar to Google Now).
- Created desktop applications for numerous clients, combining features such as RSS tracking, weather information, and commenting.
- Built various in-house websites and applications for top 500 enterprises.
Technologies: C#, PHP, JavaScript, T-SQL
Scalable Architecture Developer in Guangzhou, Guangdong, China
Member since February 9, 2015
Koen is a passionate developer with a love for a wide range of technological practices and a keen eye on quality and communication. He brings over a decade of experience in building services and applications, both solo as well as in teams. He can be trusted to complete a project on time and within budget, while staying true to expected quality.
Koen is now available for hire
Experience
- .NET, 12 years
- T-SQL, 11 years
- Scalable Architecture, 10 years
- Bootstrap, 5 years
- Azure, 5 years
- TypeScript, 4 years
- Angular, 2 years
- ASP.NET Core, 2 years
Availability
Part-time
Preferred Environment
Microsoft Visual Studio
The most amazing...
...thing I've created is an app to help people with limitations get online using only their voice. This was long before the iPhone became popular.
Employment
Experience
- Postvid Consumer Platform (Development)
Postvids are a new breed of direct marketing and impact marketing communication tools. Postvids drive home your brand and campaign messages through hi-definition LCD screens and powerful audio speakers encased in a full color, fully customizable, printed brochure or booklet.
- WeTrada Website (Development)
You get together with others who want to buy the same product. You buy the things you love together as a group! Now it’s possible to place orders directly with the manufacturer without having to deal with cost-adding merchants and middle men. Straight from the factory to your home. The savings are spectacular!
- Koen is a mentor in the Toptal Global Mentor’s Program. This program is a partnership between Toptal and General Assembly to provide high quality mentorship for students from minority and low income backgrounds who are looking to begin their careers as professional software engineers. Koen shows commitment to diversity in tech by mentoring a General Assembly student every week for a year, covering everything from coding tips and tricks to advice on making it in the industry.
Skills
Languages
C#, T-SQL, SQL, JavaScript, TypeScript, PHP, Python, Java, F#, ScalaFrameworks
ASP.NET Core, ASP.NET Core 2, Aurelia, .NET, ASP.NET, Durandal, ASP.NET Web API, ASP.NET MVC, Bootstrap, Angular, AngularJS, Windows Communication Framework (WCF), PhoneGap, Cordova, Knockout.jsPlatforms
Azure, Azure FunctionsLibraries/APIs
jQuery UI, jQuery, SignalR, Node.js, Twitter API, LinkedIn API, Facebook APITools
Microsoft Visual Studio, Git, Subversion (SVN), MercurialStorage
Azure Cosmos DB, MySQL, Microsoft SQL ServerOther
Scalable Architecture, Windows Presentation Foundation (WPF), Big DataParadigms
Functional Programming, Reactive Programming, Concurrent Programming
Education
- Bachelor's degree in Computer Science2005 - 2008Windesheim University - Netherlands
