My DHL Parcel

Working on a modern all-in-one shipping service, responsible for developing business and consumer applications, including various microservices to support operational processes. Developing international shipping labels for different products and printer types, customs integration, product lifecycle management, customer APIs, desktop integration for 3rd party shipping tools. Responsible for the reliable operation of the platform and providing 3rd line support.

Scala Typescript Akka Azure Cassandra ElasticSearch iText PDF Kafka Play Docker React Redis Scala FX Tapir Mesos + Marathon IntelliJ Visual Studio Code Full stack Microservices Data driven architecture

RIPEstat

RIPEstat is a large-scale information service and the open data platform of the RIPE NCC. I was responsible for developing data sets to obtain real-time insight in the state of the internet, while also allowing arbitrary time-series. The data is stored using HBase in a large-scale Hadoop cluster.

Java Hadoop HBase Map/reduce IntelliJ Big Data

Large-scale enterprise collaboration tooling

Responsible for the systems design, architecture, implementation and operations for a collaboration software application with a small team. Using CQRS and event sourcing to maintain a platform neutral journal with complete history of system interactions based on Akka Persistence, Protobuf and Cassandra. Building real-time projections using Kafka with Akka Streams and best-of-breed technologies. Implemented a front-end based on game mechanics using Typescript, Phaser and AngularJS.

Scala Java ES6 C# Swift Play Framework Akka Kafka Cassandra MongoDB ElasticSearch PhaserJS IntelliJ XCode Unity CQRS Event sourcing Reactive Real-time WebGL

Whois database

Reimplement the Whois database, adding functionality and fixing long-standing issues. Replacing query, update and near real-time mirroring applications. Building a legacy proxy to support the transition. Implemented using reactive non-blocking IO based on Netty.

Java Play Framework Netty IntelliJ Eclipse Event sourcing Real-time mirroring

DRM platform for publisher

Developing a DRM system for a large publisher. Automated functional testing using Geb and Spock. Added new features to the existing application using CQRS and event sourcing with the Axon framework.

Java Axon CQRS Eclipse Event sourcing Domain-driven design

Cardiac monitoring

I was responsible for single-handily integrating a variety of applications to reliably allow remote monitoring of cardiac arrhythmia by healthcare professionals.

Java Oracle Spring JAX-WS Vaadin Eclipse

Job portal and business applications

Building a new white-label web portal for Randstad companies for job searchers, employees and HR professionals using JSF, ADF, Oracle Rich Client. Consume and transform services data using Oracle ESB and BPM.

Java JSF Oracle ADF Oracle ESB Oracle BPM Oracle JDeveloper Event sourcing Domain-driven design

GX Webmanager

I worked with the solutions division of GX WebManager in Amsterdam to provide consulting to their customers and help them with the implementation of custom functionality and adopting best practices. I helped various clients improving the quality and predictability of their software development processes.

Java GX WebManager OSGI Eclipse

International job sites

As a lead developer I was responsible for the architecture and implementation of a white label international job site. This job site provided the default option to modernize and unify international Randstad brands and was successfully adopted in multiple countries. Our agile team delivered new functionality on a weekly basis. We used a domain driven approach. With object relational mapping we managed to implement a rich domain model while keeping database access efficient. One of the key features was job search, where users could define advanced queries and filter down using a multi-faceted search, which was very novel at the time. Static content and layouts were maintained in a CMS and interwoven with application sections in our back-end.

Java Spring Spring security Spring WS Hibernate Struts 2 Weblogic Oracle Maven Apache Hudson Solr Roxen CMS Eclipse Component based development

Holiday Portal

Holiday portal for searching and booking a diversity of accommodations. I was responsible for the software architecture and implementation to build a white-label application that allowed various accommodation types, like campsites, bungalows and hotels.

Java Spring Hibernate JSF Apache MyFaces Eclipse ORM

Dutch lottery website

Implementing the website and back-office for the Dutch state lottery.

Java Spring Hibernate Eclipse ORM Component based design

Logistics

Implementing a new business system to support a new good-driven logistics process.

Java EJB 2 IBM DB2 VisualAge for Java Visual modeling Component based design