Joachim Hofer
Senior Principal Engineer at Zalando SE
Berlin, Germany
Summary
👤
Senior🎓
Top SchoolJoachim Hofer is a Senior Principal Engineer based in Berlin with 16 years of hands-on experience delivering resilient backend systems and driving engineering quality at scale. A dev-first software craftsman, he combines deep practical expertise in reactive programming with a penchant for improving type safety, synchronization, and test coverage—as evidenced by notable contributions to the widely used RxJava and RxScala projects. At Zalando he progressed from software developer to senior principal, applying pragmatic leadership to complex distributed problems while still writing and reviewing core logic. His background as a Scrum Master and lead developer reflects strong delivery discipline and team coaching in product development. Joachim continuously seeks technical learning opportunities and treats architectural obstacles as invitations to innovate. He pairs academic training in computer science with a steady track record of shipping robust, well-tested code in open-source and enterprise contexts.
16 years of coding experience
2 years of employment as a software developer
Diplom-Informatiker, Computer Science, Diplom-Informatiker, Computer Science at Friedrich-Alexander-Universität Erlangen-Nürnberg
German, English
Stackoverflow
344reputation
46kreached
1answer
0questions
Github Skills (17)
rxjavafx10
testing10
java10
scala10
javas10
rxjava10
functional-programming10
concurrency10
sbt9
platform-independent8
cross-platform8
multiplatform8
api-design7
githubaction-workflow6
publish6
Programming languages (6)
Github contributions (5)
ReactiveX/RxJava
Mar 2013 - Sep 2013
RxJava – Reactive Extensions for the JVM – a library for composing asynchronous and event-based programs using observable sequences for the Java VM.
Role in this project:
Back-end Developer & QA Engineer
Back-end Developer & QA EngineerContributions:146 commits in 5 months
Contributions summary:Joachim primarily contributed to the `OperationCombineLatest` class, making changes to tests and the core logic. These changes involved implementing the correct semantics for combining latest values from multiple observables and adapting the tests to reflect the changes. The user also worked on improving the type safety of the code. The user also fixed javadoc and comments, and cleaned up synchronization issues.
asynchronousrxjavareactive-streamsreactive-extensionsjvm
ReactiveX/RxScala
Aug 2013 - Oct 2014
RxScala – Reactive Extensions for Scala – a library for composing asynchronous and event-based programs using observable sequences
Role in this project:Back-end Developer
Back-end DeveloperContributions:29 commits in 1 year 1 month
Contributions summary:Joachim contributed to the RxScala library, focusing on improvements and adjustments to core functionality. Their work involved adding variance to functions, updating the library to new Scala versions, and generalizing code related to observable covariance. The user also adapted and extended tests to reflect changes, particularly related to zip operations and generics. Furthermore, they integrated continuous integration tools, setting up the project for automated builds and publishing.
asynchronousfunctional-programmingreactive-streamsreactive-extensionsscala
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