Janusz Wiśniowski, Developer in Wrocław, Poland
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Janusz Wiśniowski

Verified Expert  in Engineering

Atlassian Plugins Developer

Wrocław, Poland
Toptal Member Since
January 1, 2017

Janusz is a skilled software engineer who's been in business since 2006. He's a quick learner, reliable, self-reliant, and precise. He's worked on many interesting ventures using a variety of modern technologies and programming languages on different operating systems (including multi-platform applications). He also has extensive experience working in teams distributed across the globe (including fully remote work with teams in APAC and NA).


Infusion Development
Microsoft SQL Server, Oracle, Bootstrap, jQuery, AngularJS, JavaScript, JAX-RS...
Credit Suisse (via Infusion Development)
Entity Framework, Windows Communication Foundation (WCF)...
Opera Software
Pike, JavaScript, C++




Preferred Environment

IntelliJ IDEA, Git, Linux

The most amazing...

...project I've contributed to is Opera Mini, which grew from twenty million users in 2009 to over 180 million in 2012.

Work Experience

Software Consultant

2014 - 2016
Infusion Development
  • Contributed to many short-term delivery projects in various technologies (both front-end and back-end) for both external (mostly enterprise) and internal customers.
  • Collaborated to develop the rate calculation module in an insurance renewal SPA web application for MetLife.
  • Co-designed a client-server FX trading application with a desktop JavaFX client and AKKA messaging for Wells Fargo. Later implemented the window manager module allowing the users to set up complex window layouts (grouping and stacking) and save them as layout profiles. The complexity of the component required extending the standard JavaFX with low-level WinAPI calls.
  • Worked on Infusion's own product, Pulse, a retail device management service. It provides software installation, upgrading, monitoring, and metrics collection for a group of devices (phones, kiosks). I developed a supporting dashboard application for reporting aggregate metrics from multiple Pulse environments.
  • Performed architecture and security reviews for internal applications.
  • Created a plugin for embedding custom JIRA-sourced reports and visualizations in Confluence to be used in sales documents and reports.
  • Worked on a few small plugins for internal systems support, mostly for Atlassian products.
  • Converted a batch-driven Apache Spark app to stream processing (Spark Streaming/Kafka) for Barclays. Also created a test data generator for the engine.
  • Developed an ASP MVC web application for managing employee feedback sessions with a Bootstrap and jQuery-powered front-end and Microsoft CRM 2016 as data storage.
  • Extended the Spring MVC REST API for the next versions of iOS and Android mobile apps for PLS Logistics. The project was on a fully remote team spread across multiple timezones.
Technologies: Microsoft SQL Server, Oracle, Bootstrap, jQuery, AngularJS, JavaScript, JAX-RS, Spring, JavaFX, Java, Windows Presentation Foundation (WPF), ASP.NET Web API, ASP.NET MVC, C#, Atlassian SDK

Software Consultant

2012 - 2014
Credit Suisse (via Infusion Development)
  • Helped Infusion deliver a toolset to support Credit-Suisse's main risk calculation engine, PriMo. The end product was called SWorM ('Scheduler WORkflow and Monitoring') and it improved the way the risk calculations run on top of PriMo are scheduled, designed, planned, and audited.
  • Engaged in the design and kick off of SWorM in the early stage of the project.
  • Joined the UI development team. We managed to deliver a consistent, reliable, and usable user experience for SWorM coherent with other applications across the bank.
Technologies: Entity Framework, Windows Communication Foundation (WCF), Windows Presentation Foundation (WPF), Reactive Extensions, C#, .NET

Software Engineer

2009 - 2012
Opera Software
  • Worked in the Opera Mini department, delivering a product which brings web-browsing capabilities to almost any device and provides a highly effective network traffic optimization engine.
  • Engaged in developing Mini Server, a large-scale cloud back-end for the Opera Mini client application.
  • Delivered many successful Opera Mini customizations for major customers from the mobile industry including Vodafone, T-Mobile, Verizon, SKT (South Korean Telecom), Bytemobile, TATA, and Motricity.
  • Managed projects for the customer's engineering teams (working on SOWs, release plans, planning functionality, managing resources).
Technologies: Pike, JavaScript, C++

Software Developer

2007 - 2008
Power Media
  • Helped rewrite the trip-selling engine at Travelplanet, Poland's biggest online travel broker.
  • Contributed to the implementation of the process of purchasing a trip online (including payment gateway integration).
  • Worked on integrating data supplied by multiple trip vendors in a number of formats.
Technologies: Microsoft SQL Server, C#, ASP.NET Web Forms

Software Developer

2006 - 2007
  • Made an academic project of integrating InsERT's flagship SubiektGT with the osCommerce online store solution going commercial as oscGT.
  • Created an HTML editor for Sello, an online sales automation tool.
Technologies: Microsoft Foundation Class (MFC) Library, Microsoft Foundation Classes (MFC), COM, ATL, C, Microsoft SQL Server, MySQL, PHP, .NET, C#

Stack Overflow

In 2015, I started contributing to Stack Overflow. It brings me a lot of fun to go out there and help people every once in a while.
2002 - 2007

Master of Engineering Degree in Network Information Systems

Wroclaw University of Science and Technology - Wrocław


jQuery, Jira REST API, ATL, Microsoft Foundation Class (MFC) Library, Reactive Extensions, Entity Framework, JAX-RS, Microsoft Foundation Classes (MFC)


IDEA IDE, Git, IntelliJ IDEA, Atlassian SDK


Spring MVC, AngularJS, Swagger, Hibernate, Jersey, Bootstrap 3+, Spring Boot, .NET, ASP.NET Web Forms, Windows Presentation Foundation (WPF), ASP.NET MVC, ASP.NET Web API, Spring, Bootstrap


JavaScript, C#, Java, CSS, SQL, HTML, PHP, C, C++


Test-driven Development (TDD), Agile, REST


Windows, Linux, Docker, JavaFX, Oracle, Oracle Database


Spring Data, Microsoft SQL Server, MySQL


Atlassian Plugins, COM, Windows Communication Foundation (WCF), Pike

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