Jeroen Leenarts

Software developer

Last updated: November 2014

About me

I am a software developer currently specialized in iOS developer. I like to utilize a communicative style of working. My experience has shown that interacting with my stake-holders, fellow developers and end users has a positive impact on the resulting product. By utilizing my broad knowledge I am capable of quickly switching between conceptual and implementation levels of thinking. I do have a preference for the more technically challenging problems.

I attended Hogeschool Windesheim in Zwolle. It was a four year bachelor level Computer Science program.

My resume is based on the grayscale theme. Grayscale is a free Bootstrap 3 theme created by Start Bootstrap.

Apps developed

These are the apps I worked on.

ING InsideBusiness

The ING Bank released InsideBusiness on July 1st 2015. In the year prior to it's release I was involved with building the network security layer. It is a layer using several encryption methods to ensure secure and non repudiable communication.


For the Dutch CocoaHeads communities help an app was created listing several interesting bits of information about things related to the Dutch CocoaHeads.

ING Banking App

The ING Bank released a mobile banking app in october 2011. Over a period of over two years I was involved with the development of various features on the ING Mobile Banking iOS App. The iOS app was developed by a team of 5 developers of which I was part. The team operated in a larger context with a number of other teams providing the server side code and implementations for other mobile platforms.

The app has a consistent 4.5 star rating.

XebiCon Schedule App

The XebiCon schedule app was developed in my evening hours while working my day job at Xebia. It is a backed conference schedule app. It provides it's end-users an up to date overview of the events planned during the XebiCon 2014 conference. All data within the App is regularly updated from the back-end.

Xebia Essentials App

The Xebia Essentials app was developed by a co-worker to showcase the Xebia Essentials cards. During it's maintenance I helped by adding features, fixing bugs and updating the codebase. Xebia: "Software Development Done Right". More information:

Seb@stiaan School App

The Seb@stiaan school app is an app for a primary school in the Netherlands. With this app, end users are able to receive information and updates from the team at the Seb@stiaan School. It is targeted at the children's parents. Information is regularly updated by the team at Seb@stiaan school through the App.


September 2013 till…

Somehow I rolled into the Dutch CocoaHeads and got it's stewardship.…


These are the projects and assignments I work(ed) on for Xebia…

February 2012 till…

ING Commercial Banking

June 2014 – ongoing
iOS, Xcode, crypto, Scala

Switched to the ING Commercial Banking branch as a iOS security specialist.

ING Banking

Februari 2012 – June 2014
iOS, Xcode, REST

Worked on the best banking app on the Dutch market at the ING Netherlands. On this project I was one of five iOS developers working on the iOS version of the ING banking app. All work was done in an agile workflow and encompassed all aspects of a senior engineer on a software development project.

Info Support

These are the projects and assignments I worked on for Info Support…

February 2002 till January 2012

Nederlandse Spoorwegen
(NS, Dutch Railways)

April 2011 – December 2011
ANT, IBM RTC, Eclipse, Oracle WebLogic 11g

Back once again at the Nederlandse Spoorwegen (NS, Dutch Railways) with the role of software integrator on the Eclipse based planning application project. Unfortunately further details can still not be disclosed at this time.

Info Support

October 2010 – April 2011
Objective-C, XCode, iOS SDK, REST, .NET, Core-Plot

Developed an iPad application for the Info Support Professional Development Center. The goal of this application was to provide a visual representation of the key points of interest of various in-house software development projects. The iPad application presents a portable, visual representation of the status/health of a software development project.


October 2010
Objective-C, XCode, iOS SDK, REST, .NET, Core-Plot

For a customer in the finance market a proof of concept was developed. This effort had very strict constraints on allotted time and budget. Ultimately the proof of concept was a success but the project did not proceed due to being out-bid by a competitor.

Nederlandse Spoorwegen (NS, Dutch Railways)

September 2010 – October 2010
Eclipse RCP, GEF, J2EE

Back for the second time on the same project at the Nederlandse Spoorwegen (NS, Dutch Railways). For their Eclipse Rich Client based application the team I part of was tasked with the rebuilding of certain dynamic diagrams. This involved Eclipse RCP and GEF based development.

MITS Company

March 2009 – September 2010
EJB3, JBOSS, JSF, JasperReports, SOA

The MITS Company requested my help for the implementation of a billing system to help further automate their financial processing of customers. The system looked simple enough to implement on first thought, but because of specific business needs a lot of flexibility needed to be added. The goal of this project was to implement a system enabling the business to generate invoices to customers based on the services and data transfer volumes. The customers themselves mostly operate by buying the services from MITS wholesale and then reselling these to their respective clientele. Due to this structure invoices are created for each customer based on the clientele services by the customer of the MITS company.

With the MITS Billing project I took part in the implementation of the system. Besides my technical expertise as a software developer I was tasked with providing guidance to several junior employees. The architect of the system is based on the current architectural recommendation written by my employer InfoSupport.


Oktober 2007 – March 2009
Eclipse RCP, XML, XML Schema, XSLT, WebSphere

For the vtsPN (a company responsible for the implementation and exploitation of IT solutions for the Dutch police services) I have been involved with the maintenance of one of their broker applications. The application deals with investigative data from various national and international sources. The application implements an XML SOAP based interface to front-end applications. Through this SOAP interface front-end applications are able to request data from the various non-unified back-end systems in a unified data format. To maintain this application a workbench application was built and maintained. By importing the back-end service definitions the workbench application was able to allow the generation of the broker configurations after receiving user input on how to map the back-end services.

On this project I was responsible for the maintenance of the workbench product. The workbench product was an Eclipse RCP based application. I also was the technical reference concerning all matters related to XML Schema and XSLT. I was also responsible for the upgrading of the application from WebSphere 5.1 to WebSphere 6.0.

Cost Engineering

July 2007 – September 2007
JasperReports, Java 6, Swing

At a small company located in Zwijndrecht I was involved with the building of reports within their current development version of their cost engineering application. The work involved interpreting functional requirements into a working report. The application is to be used by large corporation involved with large proces industry (e.g. oil, farmaceutical).

ING Netherlands

January 2007 – June 2007
Maven 2, Java, J2EE, Python, WebSphere, Ant

At the ING Netherlands a software development project was migrated from the existing Ant based build scripts to a Maven 2 based build script. The objective was to display a convincing case study to support a ING wide introduction of Maven 2 based build scripting. The existing Ant and new Maven 2 scripting both extensively use Python scripting. Most applications are to be deployed to IBM WebSphere application servers.

Nederlandse Spoorwegen(NS, Dutch Railways)

January 2005 – December 2006
RUP, UML, J2EE, Eclipse RCP

At the Nederlandse Spoorwegen (NS, Dutch Railway) an Application was developed involving the Eclipse Rich Client Platform. The application should enable all users of the dutch rail infrastructure to plan all Dutch railway movements more efficiently. The planning involves infrastructure, material and personnel for all trains on the Dutch railway network, this includes all passenger and freight trains.

Further details can not be disclosed at this time.

PSO2, Dutch police services

September 2004 – December 2004
RUP, UML, J2EE Web components, Model Driven Architecture.

For the Dutch police services an application had to be developed called PSO2. PSO stands for “Politie Suite Opsporing” which basically means “Police Investigation Suite”. The goal of the project was to build a supporting application for police related investigation of the Dutch Police and the Criminal Investigations Department. In this process a number of information sources were available within the Dutch police network that had to be disclosed and be made accessible via a web based front-end. One of the systems PSO2 would connect to was Everest (see my previous project experiences).

In this project I fulfilled the role of developer. My tasks included developing and maintaining a JSP tag library. There were also a number of maintenance related activities on a number of framework components which was based on the OMG Model Drive Architecture principles. Areas of work included expanding the event handling mechanism and building audit logging facilities into the event mechanism.


June 2004
RUP, UML, functional design, Oracle 9 Portal, Java.

For the rebuild of an existing application there were no functional specifications available. To make sure that a realistic offer could be developed by a number of contractors, the system owner tasked me and a colleague to make a rough analysis of the majority of the functionality of the system. This basically involved analysing the existing implementation. The application involved serves about 200.000 users. The users are Dutch companies. Every company in the Netherlands has to deduct certain taxes of of the wages of their employees. The system provides this information to a majority of all Dutch companies. All tax rates are based on a number of variables which depend on the work performed by the companies. The companies can access their “personal” tax rates through this system. The current implementation was based on Oracle 9i Portal Server.

Everest, Dutch police services

February 2004 – April 2004
J2ee, Struts, Websphere 5, Junit, XML, XML schema, XSLT, JSP

In this project I was a Java developer in the web client team of the Everest Application. Activities involved implementing gui functionality in the the Struts based web interface. The web application uses Struts Tiles. These Tiles contain the presentation as JSP snippets.

The Everest program contained a number of projects to improve the Dutch Police information infrastructure. The goal of the program was to develop a central nation wide information system containing Dutch, European and worldwide warrant information. The system should be available to all authorised Dutch parties involved in criminal investigation.

Info Support

July 2003
J2EE, Struts, WebSphere Application Developer 5

Internal training program to improve existing knowledge of IBM WebSphere 4 towards IBM WebSPhere 5. Part of the program was a 3 week long development trial on building J2EE applications, The web part of the application was based on Apache Struts.

Info Support CRM

April 2003 – June 2003
IIS5 server met ASP.NET, RUP & C#, architecture

Developer on an in-house developed CRM package. Co-author of the architectural documentation. In the elaboration phase of the project several standardised components were developed and tested. A auto build environment was also implemented based on nAnt.

Web Performance Tester

March 2003
Windows 2000 server, IIS5 server met ASP.NET, Jakarta JMeter, Microsoft web stress tool

Implementing and executing a http stress tests on a web application. Several dynamic application pages and webservices (SOAP over http) had to be tested for performance.


January 2003 – February 2003
ASP.NET/C#, Visual Studio .NET

The application developed in the period of February 2002 – June 2002 was ported to Microsoft .NET. This involved a complete re write of all code. In this project the developers were given free hand concerning the implementation of the system.

In this project elements of extreme programming were used. The planning was based on a set date given by the developers. All functionality was set in stone.


September 2002 – December 2002

Introduction into Microsoft .NET. A lot of time and effort was invested into getting to understand .NET. Several small scale implementation were developed to exercise the theory. The end result was a MCAD for .NET certification.

Milliways Internship

February 2002 – June 2002
DSDM, IBM WebSphere 4.0, Visual Age for Java, WSAD 4, JUnit

Implementing a virtual lunch room. This was a two man project. The project resulted into a fully documented and production ready application. Co-workers are now able to order lunch from their desk from the local lunch room.

Contact Me

Feel free to email me to provide feedback or post inquiries, give suggestions, or to just say hello!