FRATCH

Recommended expert

Slovakia

Experience

Aug 2025 - Oct 2025

3 months

Senior Developer

JOS GROUP s. r. o.

QUART (Quality Assurance Radio Transmission) is a small application used at ORF, which receives broadcasts from the Editorial System (RedSys), manages broadcasts (create, edit, etc.), creates tickets in Omnitracker and manages final reports (create, generate PDF, etc.)
Task: analysis, development and testing
Development and testing with C#, .NET 9.0, REST services, Unit/xUnit tests, Hexagonal architecture, DDD, HTML5, CSS, TypeScript, Angular, Docker, AWS
Environment: MS Visual Studio 2022 on Windows 11
Client: ORF

Sep 2024 - Dec 2025

1 year 4 months

Senior Developer

JOS GROUP s. r. o.

Minol is a CRM application that supports Minol's business processes (heating and operating costs, energy, etc.)
Task: analysis, development and testing
Implementation of C# and JavaScript CRM plugins and customizations with C#, .NET 7.0, REST services, Unit/xUnit tests, JavaScript, jQuery, Bootstrap, TypeScript, Microsoft Dynamics 365, CRM SDK, SAP
Environment: MS Visual Studio 2021 on Windows 10
Client: Minol

Aug 2024 - Oct 2024

3 months

Senior Developer

JOS GROUP s. r. o.

HWBO is a web application to support the craftsman bonus for flood/storm damage (painting, tiling, drying or clearing work)
Task: analysis, development and testing
Development with C#, .NET 4.8, ASP.NET MVC, Entity Framework, web services, ASP.NET Razor, Unit/xUnit tests, jQuery, Bootstrap, TypeScript, MS SQL, Scrum, Azure DevOps
Environment: MS Visual Studio 2019 on Windows 10
Client: Federal Computing Center (BRZ)

Jul 2021 - Mar 2022

9 months

Senior Developer

JOS GROUP s. r. o.

Leiner Application project includes several subprojects to support the sales process for customers, including combining assembly and delivery with price calculation and adapting existing web services
Task: analysis, development and testing
Development with C#, .NET 4.8, Entity Framework, REST services, Angular, TypeScript, Bootstrap, Angular Material, xUnit tests, MS SQL, Scrum, Azure DevOps
Environment: MS Visual Studio 2019 on Windows 10
Client: ItsDone Holding GmbH (Kika, Leiner)

Oct 2020 - Jul 2024

3 years 10 months

Senior Developer

JOS GROUP s. r. o.

COFAG is a web application to support the Austrian economy in the corona crisis with guarantees and fixed cost grants, from application through evaluation to approval and payment
Task: analysis, development and testing
Development with C#, .NET 4.8, ASP.NET MVC, Entity Framework, web services, ASP.NET Razor, Unit/xUnit tests, jQuery, Bootstrap, TypeScript, MS SQL, Scrum, Azure DevOps
Environment: MS Visual Studio 2019 on Windows 10
Client: Federal Computing Center (BRZ)

Jul 2020 - Sep 2020

3 months

Senior Developer

JOS GROUP s. r. o.

Azkaban is a web application supporting mobile device unlock procedures
Tasks: analyzing, developing, and testing
Development using C#, .NET 4.8, Domain Driven Design, Onion Architecture, Entity Framework, REST Services, ASP.NET Blazor, xUnit tests, MS SQL, Scrum, Azure DevOps
Environment: MS Visual Studio 2019 on Windows 10
Client: Hutchison Drei Austria GmbH

Nov 2019 - Jun 2020

8 months

Senior Developer

JOS GROUP s. r. o.

PA3000 is a web application for the personal agenda of the state office staff (time booking, travel order management, pool car management, travel expense subsidy, assignment and transfer fees) with approval workflows, admin and reports, communication with external systems (Interflex, RK, IPA, etc.)
Tasks: analyzing, developing, and testing
Development using C#, .NET 4.8, ASP.NET MVC, ReSharper, Entity Framework, Web Services, ASP.NET Razor, unit/xUnit tests, jQuery, Bootstrap, TypeScript, MS SQL, Scrum, Azure DevOps
Environment: MS Visual Studio 2019 on Windows 10
Client: Office of the Lower Austria State Government

Jun 2019 - Oct 2019

5 months

Senior Developer

JOS GROUP s. r. o.

Vita is an integrated system for the Wien Social Fund (FSW) for provider management, customer management, and company control, supporting core processes efficiently
Tasks: analyzing, developing, and testing in the ORG and KAT modules
Development using C#, .NET 4.8, ReSharper, Entity Framework, Domain Driven Design, SOA, self-hosted WCF services, unit/xUnit tests, SpecFlow tests, GIT, Angular 8, jQuery, Bootstrap, Telerik Kendo UI, MS SQL, CSS3, HTML5, Azure DevOps, Scrum
Environment: MS Visual Studio 2017 on Windows 10
Client: Wien Social Fund (FSW)

Apr 2019 - Aug 2019

5 months

Senior Developer

JOS GROUP s. r. o.

ZRV Sync Manager is a control application for the Central Electronic Legal Communication (ZRV) and utilities for monitoring, control, and reporting for Rubicon applications (PAD/VSTV…) via ERV services
Tasks: analyzing, developing, testing, troubleshooting
Development using C#, .NET 4.7, ReSharper, Entity Framework, SOAP, REST, WCF service, MS SQL, XAML, WPF, MS SQL update scripts, Azure DevOps
Environment: MS Visual Studio 2017 on Windows 10
Client: Austrian Federal Ministry of the Interior (BMI)

Jun 2018 - Oct 2018

5 months

Senior Developer

JOS GROUP s. r. o.

CONTENTShare is a WPF application for sharing documents with customer-specific sections (invoice management, customer support, etc.)
Tasks: analyzing, developing, and testing
Development using C#, .NET 4.6, ReSharper, Entity Framework, MVVM, MS SQL, XAML, WPF, SVN, WCF service, IIS, unit tests, SQL stored procedures
Environment: MS Visual Studio 2015 on Windows 10
Client: CS-nine GmbH

Nov 2017 - Aug 2019

1 year 10 months

Senior Developer

JOS GROUP s. r. o.

BMI Tool Manager automates tests of various ASP.NET Rubicon applications in the operations of the Ministry of the Interior and provides a quick overview of issues with screenshots
Tasks: analysis, development, testing, error analysis
Developed with C#, .NET 4.7, ReSharper, Entity Framework, Caliburn.Micro, MVVM, MS SQL, XAML, WPF, TFS, Selenium Chrome Driver
Environment: MS Visual Studio 2015 & 2017 on Windows 10
Client: Austrian Federal Ministry of the Interior (BMI)

Jul 2017 - Oct 2017

4 months

Senior Developer

JOS GROUP s. r. o.

Portfolio Viewer is an AngularJS application providing an overview of energy portfolios (gas, electricity, etc.) for better decision making in trading
Tasks: analysis, frontend development and testing
Developed with JavaScript, AngularJS, Node.js, grunt, karma, XML, JSON, CSS3, HTML5, jQuery, responsive web design, Bootstrap, SCRUM, JIRA, SVN
Environment: Visual Studio Code on Windows 10
Client: Kisters

Aug 2016 - Oct 2017

1 year 3 months

Senior Developer

JOS GROUP s. r. o.

EDS Transfer Pricing optimizes electricity sales through simulations based on OpenLink IRM contracts to achieve optimal selling prices
Tasks: analysis, development and testing
Developed with C#, .NET 4.6, ReSharper, Entity Framework, Caliburn.Micro, MVVM, Oracle 11, PL/SQL Developer, XAML, WPF, SCRUM, JIRA, SVN
Environment: MS Visual Studio 2013 on Windows 10
Client: OpenLink

Jul 2016 - Aug 2016

2 months

Senior Developer

JOS GROUP s. r. o.

Solvay Gas Scheduling plans gas sales with simulations based on OpenLink IRM contracts for optimal selling prices
Tasks: analysis, development and testing
Developed with C#, .NET 4.6, ReSharper, Entity Framework, Caliburn.Micro, MVVM, Oracle 11, PL/SQL Developer, XAML, WPF, SCRUM, JIRA, SVN
Environment: MS Visual Studio 2013 on Windows 10
Client: OpenLink

Feb 2016 - Jul 2016

6 months

Senior Developer

JOS GROUP s. r. o.

IRM Regulatory Reporting Desktop is a solution for reporting from IRM TradeExpress with auditing, error monitoring, and bidirectional communication with registration agencies (EFETnet eRR, REGIS-TR)
Tasks: analysis, development and testing
Developed with C#, .NET 4.6, ReSharper, Entity Framework, Caliburn.Micro, MVVM, Oracle 11, PL/SQL Developer, XAML, WPF, SCRUM, JIRA, SVN
Environment: MS Visual Studio 2013 on Windows 10
Client: OpenLink

Sep 2014 - Feb 2016

1 year 6 months

Senior Developer

JOS GROUP s. r. o.

BackBüro Apps (BB sales support app, BB order management app) support the sales of BackBüro software solutions
Responsibilities: Analyzing, task estimation, sub-project management, partial development, design
Sub-project management of a team (2 people) using HTML5, CSS, AJAX, JavaScript, jQuery, Knockout, DevExpress, single-page technology
Environment: MS Visual Studio 2013 on Windows 7
Client: bochmann. SoftwareTechnologie | MediaAgentur

Sep 2013 - Feb 2016

2 years 6 months

Senior Developer

JOS GROUP s. r. o.

BackBüro is industry software for bakers, pastry chefs and gingerbread makers to manage sales items, purchasing items, recipes and orders with a labeling feature
Responsibilities: Analyzing, designing, developing, testing, documentation, task estimation, development of controls in MFC
Senior developer of a team (3 people) using C++, SQL, MFC, XML, XSD, Scrum, Boost, RapidXML, zlib; prototypes in C#
Environment: MS Visual Studio 2013 on Windows 7
Client: bochmann. SoftwareTechnologie | MediaAgentur

Sep 2012 - Jul 2013

11 months

Senior Developer

JOS GROUP s. r. o.

ETCS-SW Test Environment (ESTE) is a testing environment for deterministic cycle simulation of the ETCS software for integration tests
Responsibilities: Analyzing, designing, developing, testing, documentation (V-Model, features, system requirements, standards EN/CENELEC/UNISIG/ERA/IEC, interface specs, architectural and detailed design), work package estimation
Senior developer of a team (5 people) using C, C++, XML-RPC, Scrum, Qt, Expat, STL, multithreading, MVB bus data transfer, Doxygen
Environment: Emacs, gedit on Red Hat Enterprise Linux Server 5.3
Client: Thales Austria GmbH

Nov 2011 - Aug 2012

10 months

Senior Developer

JOS GROUP s. r. o.

TTX-DataLoggerTool supports validation, troubleshooting and calibration in automotive systems with interfaces to CAN, FlexRay, digital, analog, MOST, LIN, RS232, recording all vehicle network data into trace files and remote control of the data logger
Responsibilities: Design (Enterprise Architect, MKS), development, documentation (V-Model), testing, configuration management (Python)
Development with C#, .NET 4.0, XML-RPC, WPF, XAML, MVVM, Silverlight, WCF RIA Services, MVC
Environment: MS Visual Studio 2010 on Windows XP
Client: TTTech Computertechnik (Audi)

Aug 2011 - Nov 2011

4 months

Senior Developer

JOS GROUP s. r. o.

OVALO ILS ECU is an integrated overlay steering system for automobiles with speed-dependent power steering assistance
Responsibilities: Analyzing, developing and testing, safety concept, documentation (V-Model), hardware simulation, DaVinci Configurator
Development of drivers (B6 PWM driver, rotor position sensor, lock-pin actuator) in embedded C (MISRA, double buffer), safety programming according to ISO 26262, IEC61508, ASIL A, N2HET PWM signals
Environment: HET IDE 2.6, TMS470 compiler, Windows XP, MicroSar AUTOSAR 3.0
Client: TTTech Computertechnik (BMW, Audi)

Dec 2009 - Jun 2011

1 year 7 months

Senior Developer

JOS GROUP s. r. o.

ETCS-SW Test Environment (ESTE) is a test environment for deterministic cycle simulation of ETCS software for integration tests
Tasks: analyzing, developing, testing, documentation (V-Model)
Sole responsibility using C, C++, XML-RPC, Scrum, Qt, STL, multi-threading
Environment: Emacs, Qt 4.6.2 on Red Hat Enterprise Linux Server 5.3
Client: Thales Austria

Aug 2009 - Nov 2009

4 months

Senior Developer

JOS GROUP s. r. o.

IOP interface implements interoperability between Test Control and Logging (TCL) and the ETCS software for simultaneous train run simulations
Tasks: developing, testing, documentation (V-Model)
Development with Embedded C, XML-RPC, Scrum
Team of 7 people
Environment: Emacs on Red Hat Enterprise Linux Server 5.3
Client: Thales Austria

May 2009 - Jul 2009

3 months

Senior Developer

JOS GROUP s. r. o.

DNN Development SMA_UK is a web application for product sales for Wyeth
Tasks: developing and testing
Development in C#, HTML, JavaScript, AJAX, CSS, XML, web services, SOAP
Team of 15 people
Environment: Microsoft Visual Studio 2008, .NET 3.0 on Windows XP
Client: ACP IT Solutions (Wyeth)

Aug 2008 - Jun 2009

11 months

Senior Developer

JOS GROUP s. r. o.

Parking is a hardware and software solution to automate parking processes with parking barrier machines, payment modules (coins, banknotes, cards), configuration via card/internet, bank communication (SityControl/SityClient, SityCollect) over GSM/GPRS
Tasks: project leadership, analyzing, developing and testing
Project management and programming in Embedded C, Scrum Master, team of 3 people
Environment: X32, Windows XP, Embedded OS Y
Client: ANF Data (Siemens, city administrations of Munich, Paris, Stuttgart, Copenhagen)

Jan 2008 - Aug 2008

8 months

Developer

JOS SOFTWARE

IFX-SPS and IFX-SPS-Compact manage products, versions and structures (hierarchies) of products; the compact variant is a stripped-down version
Tasks: analyzing, developing and testing
Development in C#, ASP.NET 1.1, SQL, XBAP, WPF, stored procedures, JavaScript, HTML, .NET 3.0 XBAP, web services, SOAP, Scrum
Team of 2 people
Environment: Visual Studio 2003 & 2008 on Windows XP
Client: ANF Data (Infineon)

Nov 2007 - Dec 2007

2 months

Developer

JOS SOFTWARE

MVB driver enables communication between PVSS (process control) and hardware over the MVB bus (e.g. in trains)
Tasks: development and testing
Sole responsibility for C++, socket programming, hooks, Win32 API, MVB bus
Environment: Visual Studio 6.0 on Windows 2000 Embedded
Client: ANF Data (Siemens, ÖBB, Wiener Linien, New York Subway)

Aug 2007 - Nov 2007

4 months

Developer

JOS SOFTWARE

VDS TestTools is a tool for testing the Traffic Data Server (VDS) and a simulation toolbox (JLo)
Tasks: development and testing
Development in Java (Swing, RMI, Jini, SAL, XML, Log4j), Scrum
Team of 4 people
Environment: JDK 5.0 on Windows XP & Linux Server
Client: ANF Data (Siemens Munich, Stuttgart)

Jul 2006 - Jul 2007

1 year 1 month

Developer

JOS SOFTWARE

Facet Editor is an extension of the Facet Builder in the Step7 Extension Package for Automation Designer 2008 for GUI-based facet creation and editing
Tasks: analysis, development and testing
Development in C#, XML, Win32 API, Scrum; tests with NUnit
Team of 5 people
Environment: Visual Studio 2003 on Windows XP
Client: Siemens AG, Moorebrunn Nuremberg

Oct 2005 - Jun 2006

9 months

Developer

JOS SOFTWARE

Code Generator in the Step7 Extension Package for Automation Designer 2006 reads facet projects and creates Step7 large-scale projects for production automation
Tasks: analysis, development and testing
Development in C#, XML, COM, Scrum
Team of 3 people
Environment: Visual Studio 2003 on Windows XP
Client: Siemens AG, Moorebrunn Nuremberg

Aug 2005 - Jan 2006

6 months

Developer

JOS SOFTWARE

Facet Builder in the Step7 Extension Package for Automation Designer 2006 creates facets (Project, PLC, Resource, OM/EM, Self Controlled Resource) for SIMATIC Manager Step7
Tasks: analysis, development and testing
Sole responsibility for C#, XML, Win32 API, Scrum
Environment: Visual Studio 2003 on Windows XP
Client: Siemens AG, Moorebrunn Nuremberg

May 2004 - Oct 2004

6 months

Developer

Together tímové riešenia s.r.o.

TRF 2004 Patent Office: extension of a Fabasoft application for configurable invoices, purchase orders, batch invoices, payment slips, and VAT number validation
Tasks: analyzing, developing, and testing
Development in Fabasoft, Visual Basic 6, Crystal Reports 6
Team of 3 people
Environment: Visual Studio 6.0 on Windows 2000
Client: Austrian Patent Office

Jan 2003 - Jul 2005

2 years 7 months

Developer

Together tímové riešenia s.r.o.

Together Document Management in TGW Groupware Framework for document management (viewing, editing, checking in/out, versioning, deleting, printing, email attachments, drag & drop, copy & paste) and embedding custom properties with Excelsior JET native compilation
Tasks: analyzing, developing, and testing
Development Server: Java Servlets, JSP; Client: HTML, XML, JavaScript; LDAP integration
Environment: JBuilder 7–9 Enterprise on Windows 2000
Client: Together Teamlösungen EDV-Dienstleistungen GmbH, Vienna

Sep 2002 - Dec 2002

4 months

Developer

Together tímové riešenia s.r.o.

EVN development: extension of a Fabasoft product with API functions (DLL) and porting Visual Basic functions to C++ COM
Tasks: analyzing, developing, and testing
Development in C++, COM, DLLs
Team of 3 people
Environment: Visual Studio 6.0 on Windows 2000
Client: EVN AG

Mar 1999 - Jun 2002

3 years 4 months

Developer

NEMETSCHEK Slovensko a.s.

Bau for Windows: custom programming and small projects in the areas of construction site controlling, logistics, financial accounting, management accounting, equipment and plant accounting, payroll/salary, SQL/ODBC drivers and master data packages
Tasks: programming and testing
Development in C/C++
Team of 3 people
Environment: MS Visual Studio 5.0–6.0 on Windows 2000, NT 4.0, 98, Linux, AIX, HPUX
Client: IBD GmbH, Karlsruhe

Industries Experience

See where this freelancer has spent most of their professional time. Longer bars indicate deeper hands-on experience, while shorter ones reflect targeted or project-based work.

Experienced in Information Technology (16.5 years), Government and Administration (7 years), Construction (3.5 years), Food and Beverage (2.5 years), Energy (2 years), and Utilities (1.5 years).

Information Technology

Government and Administration

Construction

Food and Beverage

Energy

Utilities

Business Areas Experience

The graph below provides a cumulative view of the freelancer's experience across multiple business areas, calculated from completed and active engagements. It highlights the areas where the freelancer has most frequently contributed to planning, execution, and delivery of business outcomes.

Experienced in Information Technology (24.5 years), Product Development (13.5 years), Quality Assurance (10.5 years), Accounting (3.5 years), Logistics (3.5 years), and Project Management (2.5 years).

Information Technology

Product Development

Quality Assurance

Accounting

Logistics

Project Management

Skills

Experience And Skills (1: Advanced, 2: Good Knowledge, 3: Basic Knowledge)

Programming Languages

C 1
Embedded C 1
C# 1
C++ 1
Java 3
Assembler 3
Nhet Assembler 2

Web Programming Languages

Html/html5 1
Javascript 1
Css, Xcss 1
Php 3
Perl 3

Web Libraries, Toolkits, Etc.

Bootstrap 2
Jquery 1
Angular/angularjs 1
Ajax 2
Dom 2
Xml 1
Json 2
Responsive Web Design 1

Frameworks, Libraries, Etc.

.Net Framework 1
Winforms 1
Wpf 1
Linq 2
Asp .Net 2
Wcf Services (Ria, Self Hosted) 2
Qt Framework 2
Mfc 3

Web Servers

Tomcat 3
Ms Iis 2

Design/software Architectural Patterns

Mvvm 1
Mvc 1
Ddd 2
Microservices 3
.Net Design Patterns (Gang Of Four) 2

Databases

Ms Sql Server 1
Oracle 2
Mysql 2

Operating Systems

Ms Windows 1
Linux 2
Unix 3

System & Software Testing

Nunit 1
Xunit 2
Specflow 2
Junit 3
Selenium Automation Testing 2

Configuration Management

Rational Clearcase 2
Svn 1
Git 2
Ms Tfs 1
Azure Devops Server 1

Miscellaneous

Ms Office 1
Doors 3
Misra 3
Safety Standards (Iso 26262, Iec61508, Asil) 3
Etcs Standards And Norms (En, Cenelec, Unisig, Era, Iec) 3
Doxygen 3
Rational Clearcase 3
Agile Software Development (Scrum) 1
Fabasoft 3
Aws 2
Docker 2

Languages

Slovak

Native

German

Advanced

English

Advanced

Education

Sep 1993 - Jun 1999

Slovak University of Technology in Bratislava

Dipl.-Ing., Software Engineering · Electrical Engineering and Information Technology · Bratislava, Slovakia

Sep 1989 - Jun 1993

High School, Skalica

Skalica, Slovakia

Profile

Created

January 2026

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Frequently asked questions

Do you have questions? Here you can find further information.

What languages does Ján speak?

Ján speaks the following languages: Slovak (Native), German (Advanced), English (Advanced).

How many years of experience does Ján have?

Ján has at least 26 years of experience. During this time, Ján has worked in at least 2 different roles and for 4 different companies. The average length of individual experience is 1 year and 9 months. Note that Ján may not have shared all experience and actually has more experience.

What roles would Ján be best suited for?

Based on recent experience, Ján would be well-suited for roles such as: Senior Developer, Developer.

What is Ján's latest experience?

Ján's most recent position is Senior Developer at JOS GROUP s. r. o..

What companies has Ján worked for in recent years?

In recent years, Ján has worked for JOS GROUP s. r. o..

Which industries is Ján most experienced in?

Ján is most experienced in industries like Information Technology (IT), Government and Public Administration, and Construction. Ján also has some experience in Food and Beverage, Energy, and Utility Services.

Which business areas is Ján most experienced in?

Ján is most experienced in business areas like Information Technology (IT), Product Development, and Quality Assurance (QA). Ján also has some experience in Accounting, Logistics, and Project Management.