Richard Rozsa, Developer in Gouda, Netherlands
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Richard Rozsa

Verified Expert  in Engineering

C# Developer

Gouda, Netherlands
Toptal Member Since
August 22, 2013

Richard Rozsa offers a vision of data as a self formatting entity. For more than 30 years, he's delivered top quality technical architecture, programming, testing and solutions for complex problems--on-time and within budget. He's extremely flexible and able to integrate as a standalone freelancer or within teams.


EPPlus, SQL, XPath, C#, .NET Core, REST APIs, C#.NET WinForms, C#.NET, .NET 6
Stark Assessments
JavaScript, CSS, HTML, Microsoft SQL Server, Model View Controller (MVC)...
Property Data Cloud
C#, .NET, .NET Core, C#.NET WinForms, C#.NET




Preferred Environment

Visual Studio, Windows

The most amazing... I've developed is a data transformation library that enables data in virtually any format to be easily transformed into any other.

Work Experience

Architect, Developer

2000 - PRESENT
  • Designed library layers and interfaces and created a testing framework for unit testing the many features of this product.
  • Developed various reader and writer classes that encapsulate various file formats and technologies such as SQL, XML XPath reading, and more.
  • Implemented a core mapping engine that supports the mapping of flat files as well as relational data.
  • Created a Code Configurator tool that allows the creation and editing of XML configuration files. The configurator also supports retrieval of metadata from various sources for auto-creation of configurations.
Technologies: EPPlus, SQL, XPath, C#, .NET Core, REST APIs, C#.NET WinForms, C#.NET, .NET 6

Senior Full-stack Developer

2018 - 2020
Stark Assessments
  • Developed a website using ASP.NET MVC and SQL Server to demonstrate a new testing methodology. The site demonstrates that much more can be learned about test-takers using this methodology, enabling more informed hiring choices.
  • Designed and implemented the SQL database. The management of tests was quickly implemented with a set of Excel sheets that generate SQL insert and update statements. This allowed for fast prototyping.
  • Statistical information is queried using MetaDapper, data queried from the SQL database, and an Excel sheet generated with detail and summary info.
Technologies: JavaScript, CSS, HTML, Microsoft SQL Server, Model View Controller (MVC), ASP.NET, .NET, .NET Core, REST APIs, C#.NET, ASP.NET Core, Entity Framework Core

Senior Full-stack Developer

2019 - 2019
Property Data Cloud
  • Built a framework that allowed queueing of screen scraping jobs in a multi-threaded and efficient way. Requested jobs were broken into smaller units that allowed quicker visibility of the work to be done and progress made.
  • The framework allowed for much quicker and maintainable web scraping and PDF scraping code. It also allowed for both scheduled and immediate job requests to aid support.
  • Reduced and standardized the code base significantly making maintenance of a large body of scraper code, and adding new support much more achievable.
Technologies: C#, .NET, .NET Core, C#.NET WinForms, C#.NET

Architect, Developer

2018 - 2019
  • Developed a C# WinForms application that allowed on-site windmill inspectors to select, crop, and batch images, enter blade details, and observation notes. These batches were then queued and uploaded for clients and more experienced inspectors.
  • Managed the project with a team of three onsite and remote developers, plus several testers and stakeholders. Also coordinated with two other teams with related projects.
  • Designed a simple to use user interface that inspectors found intuitive and much easier to use, resulting in much higher quality batches and a large drop in reinspection requests.
Technologies: Windows Forms (WinForms), .NET, C#, C#.NET WinForms, C#.NET

Senior Full-stack Developer

2017 - 2018
  • Maintained huge codebase for a used-car sales website, popular in European countries. The site was multi-lingual and offered different features in different countries.
  • Maintained code in ASP.NET MVC C# and SQL Server, as well as client-side code mostly in Angular 1.0. Also performed investigations with detailed functionality for teams developing and integrating functionality in other programming languages.
  • Tracked and fixed bugs using Jira as a reporting tool.
Technologies: Angular, JavaScript, CSS, HTML, Microsoft SQL Server, ASP.NET, .NET, REST APIs, C#.NET, ASP.NET Core

Senior Full-stack Developer

2013 - 2016
Lighting and Electronic Design, Inc.
  • Maintained static websites using HTML, CSS, JavaScript, and JQuery. A feature included a savings calculator for switching to LED lighting, implemented fully in JavaScript.
  • Developed tool to develop product list import file generated from a simple Excel sheet in order to support an accounting system that required thousands of permutations of custom products. This cleaned data in the accounting system in an ongoing way.
  • Developed a tool to help reconcile the current product sheets with the accounting system/sales product lists. This was part of a larger effort to update and improve the product list for sales and marketing.
  • Developed tool to store product sheets for manufacturers mainly in China, aiding designers to find parts needed for custom solutions.
  • Developed overview spreadsheet, drawing from accounting system, manually updated project status, and other status sources. This enabled better projection information resulting in more efficient and cost-effective purchasing and improved forecasting.
  • Worked on the management of manufacturing and reseller company and it's derivatives.
Technologies: HTML, Console Apps, C#, C#.NET, ASP.NET Core


2012 - 2013
GE Healthcare
  • Developed JavaScript/jQuery-generated UI with multiple views for displaying patient document records.
  • Reworked JavaScript code to resize form with window.
  • Handled server-side performance tuning in MVC application.
  • Integrated document conversion library and (together with the third-party provider) resolved library issues.
  • Implemented database and Entity Framework and defined team procedures for branching and delivery.
Technologies: jQuery, JavaScript, Entity Framework, SQL, ASP.NET MVC, C#, REST APIs, C#.NET, ASP.NET Core

Development Manager

2009 - 2009
inMotiv B.V.
  • Established an offshore development team to work in coordination with local management, architect, and business teams and designed and implemented the database.
  • Managed SCRUM process and worked in coordination with the product owner to define the product backlog and priorities.
  • Responsible for team support, motivation, hiring, and firing.
Technologies: LLBLGen, SQL Server 2008, ASP.NET MVC, ASP.NET, C#, REST APIs, C#.NET, ASP.NET Core

Management Consultant, Architect, Developer

2008 - 2009
AerData B.V.
  • Advised management multi-cultural local team on best practices for establishing offshore team.
  • Developed service that incorporated database and business layers.
  • Researched and implemented database layer using beta version of LLBLGen Pro with Linq support.
  • Handled maintenance and customer support for VB.NET windows product, C# Web Service, and MVC dashboard.
  • Designed and developed query engine for customer specific exports to various financial packages.
  • Integrated MetaDapper library for generation of financial import files in customer specific formats.
  • Jointly defined architecture of suite of products.
Technologies: Windows Communication Foundation (WCF), ASP.NET MVC, Microsoft SQL Server, Web Services, VB.NET, C#, C#.NET WinForms, C#.NET, ASP.NET Core

Developer for Intranet-based "Multi-year Deployment Plan"

2007 - 2007
  • Implemented a framework that allowed a configurable set of fields to be viewed and edited on various forms.
  • Redesigned v1 of application into a maintainable and documented product with new features, including requirement gathering and negotiating features/schedule with the product owner.
  • Created SQL Server database and implemented dynamic Excel reports generated from the database.
  • Prepared deployment plan and handed over the document to the support team.
Technologies: ASP.NET, SQL, C#, C#.NET, ASP.NET Core

Customization Manager

2005 - 2006
Net Economy B.V.
  • Established a new Customization Department, gathered all existing and promised customized projects, established procedures, and managed continuous positive financial flow.
  • Built and managed a small team of three and managed occasional full-time and regular part-time resources drawn from the rest of the company.
  • Negotiated work specifications and contracts with customers.
  • Created automated rule-based financial crime detection add on package that used government and bank defined criteria to rank events and to determine whether they should be investigated, reported, and more.
  • Developed customized features and reports and negotiated with the product owner to decide whether requested features should become a part of the main product and to decide upon a design that fits within the larger company strategy.
Technologies: Crystal Reports, SQL Server Reporting Services (SSRS), SQL Server Integration Services (SSIS), Microsoft SQL Server, Windows Forms (WinForms), C#, Fraud Analysis, REST APIs, C#.NET, ASP.NET Core

Team Lead, Architect, Developer

2001 - 2004
Covast B.V.
  • Managed development and release efforts for various product releases.
  • Established knowledge sharing environment.
  • Led brainstorming and definition meetings.
  • Designed and architected data conversion software specializing in EDI/EDIFACT formats but supporting many other formats including XML. Product also included import and export from a wide variety of transport API's including POP3, Message Queues, SQL databases, file and other transports.
  • Developed and supported core engine, multi-database vendor layer, and transport layers. Code was built on Windows and various Unix platforms.
  • Architect BizTalk integration for BizTalk releases 2000, 2002, and 2004.
Technologies: Sockets, COM+, FTP, SMTP, POP3, HTML, SAP Electronic Data Interchange (EDI), Microsoft Foundation Classes (MFC), Microsoft Foundation Class (MFC) Library, ATL, COM, BizTalk, XML, DB, Sybase, Oracle, SQL Server 2000, C#, C++, C, C#.NET

Consultant, Developer

2000 - 2001
Xpedior Benelux B.V.
  • Worked on definition and cost negotiation for product to manage help desk requests using UML.
  • Managed a small team and developed a help desk management system.
  • Designed an ASP framework for quickly building view/edit pages with role-based authorizations.
Technologies: UML, VB, Active Server Pages (ASP), ASP.NET Core


1999 - 2000
SPS/Gensys B.V.
  • Designed and developed a data conversion technology in C++. Tool integrated with existing entity code to automatically upgrade data to the new schema model. Data could be read and written from and to diverse data sources.
  • Developed and maintained software for hardware/software monitoring and automated computer installer software.
  • Worked on the development and maintenance of Windows login manager that allowed users to log into any machine and have all their electronic resources available.
Technologies: Microsoft SQL Server, Microsoft Foundation Class (MFC) Library, Microsoft Foundation Classes (MFC), C++

Business Analyst, Developer

1998 - 1999
Automotive Sales Tool Startup
  • Worked on the evaluation of interest and discussions with selected car dealers and preparation of business plan.
  • Investigated the technologies and products available for building kiosks for deployment in shopping malls.
  • Evaluated the existing car sales management software codebase.
  • Investigated the extracting details of cars for listing on sales website from VIN (vehicle identification number).
Technologies: ATL, Web Services, SQL Server 2000, C++


1996 - 1998
Microsoft Corp.
  • Led research team to design new Microsoft address book (CRM) solution.
  • Rewrote MS-Works in C++ from the original C codebase. Also authored functional specifications from existing code.
  • Resolved core architecture issues for new home product.
  • Designed a "Component upgrade via internet" strategy for new home product which served as a prototype for Microsoft wide adoption.
  • Worked on logical and physical data modeling for the new home product.
  • Developed ActiveX controls for data access on web pages.
Technologies: Microsoft SQL Server, Microsoft Foundation Classes (MFC), Microsoft Foundation Class (MFC) Library, C++

Test Lead, Developer

1995 - 1996
Microsoft Corp.
  • Team lead for performance team for Forms3, the forms component for VBA and IE3.
  • Designed, developed tools and implemented automated test lab.
  • Development of version control shell that had a pluggable low level version control product layer and allowed developers to work remotely and to always be ensured of a working branch tip.
  • Mentored test leads and testers.
  • Created test framework to improve efficiency of failure evaluation by tracking identical previous failures and expediting reproduction process and debugging of test cases.
Technologies: SQL, Microsoft Foundation Classes (MFC), Microsoft Foundation Class (MFC) Library, C++


1994 - 1995
International Technologies
  • Led development team and established requirements for SAM Project, a tool to calculate the health risks and estimated costs of various plans to dispose of the nuclear and hazardous waste stored in America.
  • Implemented the C++ layer called by Paradox to execute health risk and cost calculations.
  • Designed and developed a user interface featuring a map that allowed the graphic definition of shipping routes, and implemented a database model.
  • Established schedules and deadlines that enabled various scientific and development teams to quickly deliver a working prototype.
Technologies: Paradox, C++


1994 - 1994
Santa Fe Community College
  • Taught seminar on database design and implementation using Paradox for Windows.
Technologies: Paradox


1993 - 1994
Various projects
  • Designed and developed configuration management systems for medium-sized companies.
  • Developed a custom database engine for a text-based database.
  • Designed and developed an order entry system for lighting manufacturer with part numbers made up of several component IDs.
Technologies: ATL, Microsoft SQL Server, C++, C#.NET WinForms


1990 - 1992
Borland International
  • Developed and maintained a dBASE for Windows, as well as created a common code library used to access dBASE databases in Borland products.
  • Created detailed documentation of all dBASE features and differences in various vendor implementations (eventually released as a book).
  • Led a team of version control, integration support, network maintenance, and development-side testing group.
Technologies: Assembler, C++, C

Developer, Tester

1989 - 1990
Borland International
  • Worked on the development and maintenance of various test suites for the dBASE and Paradox teams.
  • Developed and maintained the performance tests and coordination with the development team to improve Paradox performance, as well as performance test suites for magazine reviews and communications with reviewers.
  • Created a standardized bug database for use in all Borland products.
Technologies: dBASE, Assembly, C


1982 - 1988
Various projects
  • Negotiated functional specifications, costs, and schedules with customers for Clipper consulting firm.
  • Developed data entry forms and printer-ready file generation in dBASE III+ for a company that produces a yearly catalog and address list and label printing software in BASIC.
  • Worked on the development of storyboard editor for a studio that allowed the printing of storyboard cards with text and developed various visual masks calculator for research team researching numerical patterns in classical languages.
Technologies: BASIC, Clipper, dBASE, C, REST APIs

Automated Upgrade Tool

At SPS/Gensys, a major new release of one of their new products was being prepared that dramatically altered both the product storage location as well as the schema. The upgrade tool to update the schema in data sources was integrated into the entity class code. This allowed programmers to make changes to the database and the upgrade tool would immediately support the new schema. Conversion was fully automated so development schedules never delayed testers and other pre-release users from being able to test incremental versions.

MetaDapper product

This .NET library integrates into applications and provides an interface for implementing classes that can read or write to virtually any data source/file format/API. Most commonly-used reader and writer classes are provided as a powerful mapping engine for converting from source to destination formats. A standalone configuration tool is also provided to quickly create mapping configurations.

Nuclear and Hazardous Waste Display Plan Tool

The U.S. Department of Energy was tasked with quickly creating a plan for disposing all of the nuclear and hazardous waste that had been stored for decades. There was a requirement that the solution be implemented in Paradox. Together with another developer and a team of scientists, we developed a simple interface for selecting transport routes on a map and calculating health risks and total costs extremely quickly using an external calculation library developed in C++. The project had a dramatic effect as it demonstrated that the actual costs for disposal was billions of dollars cheaper than had previously been estimated. It was the first tool that could calculate the vast amount of data for potential plans quickly enough that real evaluation of plans could be considered and over-inflated thumb-in-the-air estimates could be discounted.

Automated Testing and Performance Lab

Setup a testing/performance lab for the Forms3 team at Microsoft (the forms library used in VBA and IE3). Using both existing and new tools, the lab could run through a large volume of tests using multiple machines with a clean OS between runs, returning complete reports and highlighting changes between runs, cutting down analysis time. Note that this was before the days of virtualization. In combination with the automated build system, every developer's version control submission was validated and nightly performance runs ensured no regressions were introduced.

Dynamic Flash Page Turning Design

Designed Flash page-turning component for dynamic content. Component requests page content in the form of an XML document containing content and formatting from the server. In this way, the "book" has completely dynamic content and can grow and change immediately as new content is added. The hosting website allows users to add content through MVC web forms.

Version Control System

Developed a version control system at Borland, Microsoft, and for several smaller contracts. The system was a generic shell over replaceable low-level version control products. The system allowed users to work without checking out files (allowing them to work disconnected), kept track of files and versions each developer had retrieved, and checked in files, automatically merging with any newer versions. Check-ins would join a queue where a build/test machine would verify each submission, only adding to the branch tip in version control when successful. Teams could view the queue/build/test progress remotely. Merge/build/test failures were also stored remotely, allowing developers to resubmit fixes. In this way, the branch tip in version control was always guaranteed to be stable and developers were never blocked by another developer's broken code. While other teams suffered regularly from broken builds, users of this tool could submit frequently and were guaranteed a stable baseline.

Covast EDI Accelerator for BizTalk Server

The Covast EDI Accelerator for BizTalk Server allowed BizTalk Server to process EDI and EDIFACT documents. Early versions of this product missed critical integration possibilities in the BizTalk tools. A design was made to dynamically add menu items and buttons to the BizTalk designer. This was a complex product in that through one user interface, it updated the Covast database as well as the BizTalk storage. A framework was implemented for form creation that created dialogs, added data entry and label widgets, performed validation on user input, and stored to the Covast database.
1980 - 1982

N/A Degree in Music

University of California, Santa Cruz - California


Windows Forms (WinForms), jQuery, LINQ, React, REST APIs, Win32 API, Telerik Components for MVC, Windows API, Entity Framework, EPPlus, Microsoft Foundation Class (MFC) Library, ATL, Sockets, Active Template Library (ATL), HTTP API, ImageMagick, Microsoft Foundation Classes (MFC)


Microsoft Visual Studio, LINQ to SQL, Sendmail, Visual Studio 2012, Visual Studio 2010, Visual Studio 2008, Visual SourceSafe, Microsoft Visual C++, Notepad++, Visual Studio, C#.NET WinForms, Visio, Crystal Reports, LLBLGen, ReSharper, TFS, Flash, Microsoft Access, SAP Electronic Data Interchange (EDI), jqGrid, Audacity, Windows Installer, Adobe Lightroom, Fiddler, AutoHotkey, Google Analytics


Entity, ASP.NET Web Forms, .NET, ASP.NET MVC, ASP.NET, ASP.NET Core, Entity Framework Core, Windows PowerShell, NHibernate, .NET Core, Angular, ActiveX


SQL, XML, C, dBASE, C++, C#, HTML, HTML5, C#.NET, JavaScript, Visual Basic .NET (VB.NET), CSS, XPath, VB.NET, Active Server Pages (ASP), VB, Assembler, Assembly, Clipper, BASIC, Visual Basic 6 (VB6), VBScript, UML, Assembler x86, Visual FoxPro, Visual Basic for Applications (VBA)


Scrum, REST, Procedural Programming, Pair Programming, Service-oriented Architecture (SOA), Test Automation, Unit Testing, Waterfall Development, Test-driven Development (TDD), Refactoring, Object-oriented Programming (OOP), Data Science, Cross-platform, Continuous Integration (CI), Agile Software Development, Extreme Programming, Event-driven Programming, Concurrent Programming, Rapid Application Development (RAD), COM+, Model View Controller (MVC), Behavior-driven Development (BDD), Distributed Programming, Design Patterns


Windows, Microsoft, Oracle, Win32, Telerik, Unix, Linux, FreeBSD


SQL Server Management Studio (SSMS), SQL Server 2008, Microsoft SQL Server, Database Modeling, SQL Server Integration Services (SSIS), SQL Server Reporting Services (SSRS), JSON, Paradox, R:Base, Teradata, SQL Server 2000, Sybase, DB, IBM Db2


Ajax, SOAP, Multithreading, Lambda Functions, Architecture, Web Services, Electronic Data Interchange (EDI), CTO, Front-end Development, Web Development, Microsoft Office, User Interface (UI), Windows Communication Foundation (WCF), Network Programming, IIS, .NET 6, COM, POP3, SMTP, FTP, Console Apps, BizTalk, Unix Shell Scripting, Microsoft Office SDK, Office Add-ins, Fraud Analysis

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