Experienced software engineer (sorry, English only)

7/2018 – 3/2020

My most significant contribution at Atlassian was leading the effort to port Jira Cloud emails (over 15M emails/day) to a new notifications platform. I came up to speed with Jira emails and internals quickly, which was noticed repeatedly by product managers (“I thought you had worked on Jira for years”). Despite the challenges posed by the complexity and maturity of Jira Cloud, the project was delivered successfully and without adverse customer impact.
In the second half of my stint at Atlassian I served as the feature lead of a project focused on the performance, scalability and reliability of the issue storage system in Jira Cloud. I delivered various subprojects, such as user management, data migration and load shadowing, again, from inception to deployment and monitoring.

Main tools and technologies: Java, Kotlin, REST and Protobuf-based APIs, DynamoDB, Spring Boot, monitoring (Datadog, SignalFx).

Java (allg.), Kotlin, Spring

4/2016 – 6/2017

Concur is a mid-size company doing expense and travel management. I worked on two agile green-field projects in Java, implementing business logic, mobile-first REST APIs, high availability and automate deployments. One of the projects handled the authentication flow for all Concur mobile users (a few hundred thousand users). The other was the backend of an expense management system whose highlight was an event-based API supporting offline mobile synchronization. Both were DevOps projects and required an understanding of the whole backend stack, from the storage all the way up to the AWS ELB.

Main tools and technologies: Microservices, Java, Python, AWS, Ansible, OAuth, JSON Web Token, TLS with mutual authentication.

Amazon Web Services (AWS), Java (allg.), Python

11/2012 – 12/2015

DBCE was a startup spun off Deutsche Börse, focused on the trading and management of cloud resources. I served as the technical lead of its backend, which was a fairly complex, distributed application. Apart from working on all layers from storage all the way up to web technologies, I also provided valuable comments on the business model. We implemented WebSocket notifications, REST APIs, automated integration tests, continuous delivery and one-button deployments, all that with an agile process that was essentially Scrum with less rituals and more ad-hoc communication.

Main tools and technologies: Java (Spring, Hibernate, Wicket, Guava, Metrics), Python, PostgreSQL, TLS with mutual authentication and perfect forward secrecy, REST APIs, Ansible, WebSocket, JavaScript, HTML5 technologies.

Java (allg.), PostgreSQL

8/2010 – 11/2012

Working on a few ad-hoc commodity trading systems, implementing new features, fixing bugs and maintaining and refactoring the existing code. I came up to speed quickly: during the first two weeks I fixed all failing unit tests (almost half of them) of the first system I worked on. Within the first month I performed a long-avoided refactoring that modified the core of the system and touched virtually every source file.

Among my other responsibilities at Deutsche Börse was interviewing candidates for our team. Apart from conducting or taking part in a few dozens of interviews, I also helped make the interviewing process more effective.

Main tools and technologies: Java (Spring, Hibernate, Guava, JSF), PostgreSQL, REST APIs, JavaScript, HTML5 technologies.

Java (allg.), Spring

11/2008 – 7/2010

Taking part in the Identity Connectors project, a subproject of Sun Identity Manager focused on providing a new framework for identity provisioning. Developing a connector for the Sun Directory Server EE and OpenDS LDAP servers. Later serving as the team’s technical lead and the maintainer of the Identity Connectors framework. Responsible for incorporating feedback from Identity Manager and connector developers and for implementing API changes in both the Java and .NET/C# sides of the framework.

Main tools and technologies: LDAP, API design, core Java and .NET.

Java (allg.)

11/2004 – 11/2008

Taking part in the development of the J2EE/Java EE support in the NetBeans IDE, such as Java Persistence API and web application support. Being responsible for the database support in NetBeans. Leading the implementation team for Spring Framework support in NetBeans 6.1. Designing, implementing and reviewing NetBeans APIs.

Main tools and technologies: Java SE, concurrency, API design, Swing, JDBC, NetBeans platform.

Java (allg.)