Work I’ve Done

D2000 Smart Web - integration platform

Architected and led the replacement of the legacy JSF solution in Ipesoft’s core platform D2000 with a universal integration module serving as an API gateway and authentication server for web, mobile, and third-party systems. Over time, I evolved the module from a Java EE (WildFly) application to a Jakarta EE app with embedded libraries (Tomcat), and finally to a Spring Boot application.

Technologies: Jakarta EE, Eclipse MicroProfile, SpringBoot, CDI/SpringDI, JPA+JTA, REST API, Open API, OData, JSON Streaming, Comet/Websocket, PKI, OAuth2/OpenID Connect, Kerberos/SPNEGO, Open Telemetry, ...

OKTE ISFU - Energy Billing Data System

Architected the ISFU system (Informačný systém fakturačných údajov), a centralized platform for exchanging billing data among electricity market participants in Slovakia. Designed public APIs, led technical specifications, and prototyped a high-performance billing data message parser in Java.
Technologies: SOAP-WS, WS-Security, XMLDSig, mTLS, PKI, EDIFACT/XML,Jakarta EE/Spring Boot, JAX-WS/Apache CXF, Java Microbenchmark Harness, Jackson, Keycloak IAM, Kubernetes

Building on-premise cloud landing zone

Evaluated options for on-premise Kubernetes cluster for testing replatforming of core Ipesoft's platform D2000. Installed cluster based on Rancher Kubernetes Engine 2, MetalLB, Cillium CNI, CephFS with supporting apps like Harbor and CloudNativePG. Developed simple Helm chart for internal deployment of core product system processes.

OKTE EDC - Energy Data Center

Co-architected EDC project, Slovakia’s nationwide system for energy aggregation and electricity sharing. Designed public APIs, led technical specifications, and supported major energy distributors with integration. Developed a high-performance Java service for parallel data synchronization with existing OKTE systems.
Technologies: SOAP-WS, WS-Security, XMLDSig, mTLS, PKI, EDIFACT/XML, Jakarta EE/Spring Boot, JAX-WS/Apache CXF, Keycloak IAM, Kubernetes

Enterprise Clients & Connectors for the Energy Sector

Designed and implemented enterprise-grade clients and connectors in Java for integration within the energy sector, including: MAVIR (2017), CMIS (2018), EPEX SPOT (2018), REMIT IIP (2020), Azure IoT, Event Hub, Data Factory (2021), OKTE ISOT (2021), Office365 (2022), GELF Client (2022), ČEPS nSVR 1.5 & MMS (2022–2023), BDEW AS4 (2024)

UI Modernization for Rich-Client Applications

Envisioned, prototyped, and led an incremental UI modernization of Ipesoft’s rich-client desktop applications in React. The project began by reimplementing UI dialogs in HTML5 using the Chromium Embedded Framework (CEF), with the vision of migrating the existing codebase into a standalone web application. Designed a modular architecture enabling component reuse as a company-wide web framework for other applications.
Technologies: React, Ant Design, AgGrid, Monaco Editor

React SPA Web Applications

Architected and led the development of several single-page applications in React built on the Smart Web platform, including:
Dealticketing (2016 - 2017): Workflow-based application for electricity market transactions.
AZD Web (2018): Lifecycle management system for production data of energy facilities.
Lisper (2020): Diagnostics workflows targeting cancer treatment enhancements.
PMS (2021): Web interface for the Prediction Management System, supporting forecasts of electricity production, consumption, and commodity prices influenced by weather, market dynamics, and supply fluctuations.

Product Marketing Portal - d2000.ipesoft.com

Analyzed requirements, prototyped, and deployed the company’s core product marketing portal using the Ghost blogging platform. The portal provides a central space for presenting product features, updates, and technical content to clients and partners.

Photovoltaics Predictions optiFVE

Designed and implemented prediction algorithm for prediction of energy production of solar parks in Slovakia based on weather prediction and solar position, using Sandia National Laboratory - Photovoltaic Professionals Performance Modeling Collaborative libraries implemented in Python.

Documentation Portal - doc.ipesoft.com

Analyzed requirements, prototyped, and deployed a company-wide documentation portal using Atlassian Confluence. Implemented custom Java utilities for automated bulk import of thousands of CHM file pages and documentation export to an offline static HTML version.

Asset Management Suite (AMS)

Java Developer and Technical Lead for a long-term enterprise product (15+ years in production) built in Java EE for finance, investment firms, and banks across Central Europe (SK, CZ, AT, DE). The system supported front office, back office, accounting, controlling, and risk management.

Key contributions: Architecture & implementation of critical components: multitenant security (authorization & authentication), configuration system, custom workflow engine for orders/transactions, business calculations framework, and a reworked build system (2M+ LOC, 150+ modules across multiple languages). Integrations with external systems (Bloomberg, Reuters, SIX) using SOA, data export pipelines, and web service publishing (SOAP, REST). Technical problem-solving: application server upgrades, performance optimization, and system tuning.

Technologies: Java EE 6 (EJB, CDI, JAAS, JAX-WS, JAX-RS), Hibernate, JBoss EAP, Microsoft SQL Server, PostgreSQL, Oracle, Maven, Quartz, Swing.

AMS-WEB

Developed a modern single-page application delivering online financial information for bankers, advisors, and clients. As lead software architect from the project’s inception, I was responsible for technology choices, client/server architecture, and ongoing UI design, including multiple redesigns over the years of maintenance. The final design was made partially responsive using the Bootstrap CSS framework.
Key contributions included implementing multitenancy (permissions & styling), internationalization, reporting & charting, error reporting utilities, and Single-Sign-On integrations (SAML, OpenID Connect, and proprietary banking SSO).
Technologies: Java EE 6 (Servlet, EJB, JAAS), Google Web Toolkit, JavaScript, Bootstrap CSS.

AMS-MOBILE for Android & iOS

Architect and lead developer of a mobile application enabling clients to view financial asset data and charts on their smartphones. Responsible for the overall software architecture (client & server), technology stack selection, implementation, and delivery.

Technologies: Client – Android SDK, Retrofit, Swift, UIKit, CocoaPods; Server – Java EE 6 (JAX-RS, EJB).

Information System – Agricultural Paying Agency of the Slovak Republic

Developed an information system for the Agricultural Paying Agency, managing data on land plots, livestock, and EU subsidies provided to farmers and breeders.

Technologies: Java EE 6 (JSF, JPA, EJB), PrimeFaces, EclipseLink, WebLogic, Oracle.``

Specialized EBook Readers for Android and E-Ink Devices

Designed and implemented specialized EPUB eBook readers for Android and E-Ink devices, integrated with the platform’s server to support features such as secure downloading of purchased books.

Technologies: Android SDK, C, GTK; Server side – Java EE 6 (JPA, EJB, JAX-WS), JBoss AS, PostgreSQL.

Register Management System for Statistical Office of the Slovak Republic

Implemented REGIS - a system designed to manage complete registers of various information units—organizations, addresses, territorial units, and foreign trade—while tracking processes across the Statistical Office of the Slovak Republic.

Technologies: Java EE 6 (JPA, EJB), OpenJPA, WebSphere, Oracle, Google Web Toolkit.

Intranet Portal Solution for IKEA Supplier

Led the architecture and implementation of an intranet portal for a multinational furniture manufacturer supplying IKEA. I analyzed possible portal solutions and selected Liferay as the core platform, paired with the Vaadin framework for the frontend. The portal is integrated with multiple external systems, aggregating data from factory production lines to collaboration tools.

Technologies: Java EE 5 (JPA, EJB), Hibernate, Vaadin, MSSQL, Liferay Portal.

C++/C# Developer, .NET Technical Lead

Developed and maintained an in-house information system for companies in the industry and energy sector. Later led the migration and integration of legacy C/C++ codebase into the Microsoft .NET environment. Implemented application plug-ins for MicroStation CAD software and designed a dynamic forms engine architecture.

Diploma Project – Web Mapping Service Client

The project focused on analyzing, designing, and implementing a Web Mapping Service Client for accessing geographic maps and related data over networks. The solution was designed as a multiplatform Java application running on PDA handhelds (Java ME/Personal Profile) or via web browser (Java Applet). The application allows an interactive map and data visualization for users.

Cinque Terre National Park - proposal of IT system

As a graduate student, I participated in a workshop focused on designing recommendations for a global park and tourist information system. The system provides employees and visitors with essential information integrating external resources such as Geographic Information Systems and weather forecasts.

IEEE Computer Society International Design Competition

Participating in a global competition for undergraduate student teams to create hardware and software prototypes addressing real-world problems. Designed and prototyped eXtraordinary Message Service (XMS) with a team of students. The service allows users to alert relatives or authorities in critical situations without using a mobile device. The system can be triggered by sensors integrated into clothing, which communicate seamlessly with a smartphone. I was also responsible for implementing the Bluetooth communication layer in C++.

C and C++ Programming Languages.

Self-taught C language from the excellent czech book, and C++ through Bruce Eckel’s acclaimed Thinking in C++, deepening my understanding of programming and software design.

Database of parishioners with UI

I developed my first usable software in high school — a parishioner database for the local church. Although it was never used, it was fully functional and built in Turbo Pascal using the object-oriented Turbo Vision UI framework.

BASIC and Pascal Programming Languages

Self-taught BASIC on a ZX Spectrum clone using its user guide, I explored programming fundamentals: loops, simple algorithms, graphics, and sound. Later, I moved to Turbo Pascal, where I was introduced to the principles of structured and object-oriented programming.

Super Mario Bros

The very beginning of my journey into software. At age 7, this game sparked my curiosity about how digital worlds are built and set me on the path toward programming and technology.