Beyond trivago Tech Pt.1: Side-Projects from Our Developers

Fanatic learning is one of trivago’s core values that forms a fundamental part of our engineering culture. It’s very valuable to have curious minds around you that connect the dots to come up with new ideas and love to exchange knowledge on various topics. Since many of our engineers are involved in their own initiatives and projects outside work, we decided to introduce you to some of these side projects. The goal is to recognize their achievements and share their knowledge with our broader tech community. Take a look and feel free to reach out to any of them if you’d like to exchange on any of their topics!

Note: Since there are so many side-projects to share, we’ve decided to split them up across a mini series. Keep an eye out for part 2 coming soon!

The Bread Code

Our software engineer Hendrik Kleinwaechter has been working on engineering bread, applying software development methodology like A/B testing throughout the process. The first iterations have been tested and enjoyed by the trivago colleagues in the office, providing quality feedback. Hendrik now runs a small YouTube channel where he publishes his recipes. Together with Roberto Cucinotta, Adriano Ferracuti and Giuseppe Donati, he has created a pizza-engineering group that regularly meets up to bake pizza using traditional methods.

Follow @hendricius and check out The Bread Code on Github.

Web Engineering Meetup

Our two engineers Andy Grunwald and Dominik Siebel, are passionate about the Web, Web Engineering, Open Source, Engineering Culture, and exchanging with like-minded people. Back in 2012, both have started to get active in a local PHP Usergroup Düsseldorf. After this group felt into sleep mode, both took over the organization and organized monthly meetups. Later on, this group was renamed to Web Engineering Meetup Düsseldorf, because the group covered many more topics than the programming language PHP.

In 2019, both had a lot of experience in running engineering events. They bundled up with other (local) community leaders, (hey WebWorker NRW 👋) and organized their first non-profit and community-driven engineering conference localhost.

Fast forward to 2020. The meetup still exists and is active (due to COVID-19, meetups are paused). Due to continuous effort and consistent monthly meetups, it grew to one of Germany’s biggest tech meetups. On top of this, the format was copied by passionate community members in other cities like Aachen and Cologne.

If you are nearby, you are invited to one of our next sessions at Web Engineering Düsseldorf, Web Engineering Aachen, Web Meetup Cologne or WebWorker NRW.

Follow @andygrunwald, @milchjieper and @WebEngDUS.

Mini-Kubernetes in Docker: k3d

Our DevOps-Engineer Thorsten Klein developed the local Kubernetes development environment k3d based on Rancher Labs’ minimal Kubernetes distribution k3s. It started as a private side-project to solve a problem faced in his team at trivago: there’s no tool for local development on Kubernetes that is as fast and easy to use as docker-compose is. It soon gained some traction as people started using it in their daily development and operations work and to get started with Kubernetes the easy way. This is when Rancher contacted Thorsten via Twitter to adopt k3d into their organization namespace on GitHub to show the real integration with their project k3s and the broader Rancher ecosystem.

If you’re developing applications targeted to run on a Kubernetes production environment or just want to give Kubernetes or k3s a try, go checkout the k3d website, the project repository or some of the recordings and blog posts featuring k3d. Feel free to open issues, pull-requests or just leave some feedback via Twitter.

Follow @IWillTry42 and check out k3d on Github.


We hope you enjoyed this roundup – there are so many more initiatives to share, so might have to do some follow ups to this post. Watch this space! Our engineers are always eager to get feedback and exchange on the topics and projects they’re passionate about, so don’t hesitate to reach out to any of them directly.