This report serves as a snapshot of the current open source efforts by Zalando engineering teams and gives us insight into the current state of our projects, contributions and usage of open source inside Zalando as of June 2018.

Key insights

  • We take responsibility for our releases

    Number of released projects are decreasing compared to 2015 and 2016 and is expected to stay at 15 new projects per year, this is a deliberate strategy of mastery over open sourcing everything

  • A core group of employees are driving contribution

    The number of Zalando employees responsible for 80% of all contribution is low, sitting at 50 employees. It is however normal that a small core group is responsible for the majority of the work. The size and diversity of this group must be increased.

  • Projects are healthy and compliant

    Overall health and compliance of released projects are acceptable, there is a low number of open pull requests and the average time from contribution to acceptance is low at 85 hours. We do however see a low number of projects with a code of conduct. We will actively work on making this a requirement.

  • We share our infrastructure

    Projects released by Zalando are typically developer infrastructure projects released by Digital Foundation teams. Open source engagement for Digital Experience teams are relatively low and we want to increase their engagement.

At a glance...

There is a strong culture of Open Source at Zalando. Our engineers are expected to participate in open source and our entire tech stack is built on a foundation of Open Source projects. We therefore see a strong participation in our own projects and a desire among Zalandos to share their work with the wider open source community.

We also see challenges: not every department at Zalando have equal possibility to participation, internal process and legal grey areas are limiting access to contributions.









Key figures for all our open source projects

...The challenge faced by the Open Source Team is to take the current goodwill around Zalando’s open source work and professionalise it. This will enable Zalando to use and create open source in a consistent manner. With consistency, we can scale and streamline our open source activities and evaluate their impact and value, ensuring they are aligned with Zalando’s longer-term vision...

From everything to mastery

Our open source strategy has evolved from "open source all the things" to a focus of mastery. We set a high standard for the projects we release, both in terms of code quality, but also how we take ownership and responsibility for the community and health of a project long term. Any project that Zalando open sources have clear ownership and a long term vision for it's development and maintance.











Open source projects released over the last 4 years

Top contributors

While open source is encouraged at Zalando, it is a small number of contributors who drives the majority of all open source contributions. Just 17 Zalando employees are responsible for 50% of all commits made, and 80% of all open sourced Zalando code is contributed by 50 employees.

  • Henning Jacobs

    4212 commits
  • Willi Schönborn

    2541 commits
  • Jan Mussler

    1969 commits
  • Jörg Bellmann

    1710 commits
  • André Hartmann

    1369 commits



Of our members are contributing

Out of the current 426 people in Zalando organisations on GitHub, nearly half of them have made an accepted code contribution to a Zalando open source project.


Pull requests submitted

For all current projects, there has been made a total of 12.308 contributions, there are currently 200 open requests which are awaiting a review from project owners


Contributions made to techradar projects

Zalandos contribute to projects on the Techradar "Adopt" tier, which are part of our tech stack and have a high strategic value to Zalando

85 Hours

Average time to get a pull request merged

The average merge time is low compared to the wider open source community. It is a strong indicator our maintainers are responsive and available to contributors.


There is a general high level of open source activity over the whole year, with a constant flow of opened and completed pull requests. However, we see a substantial increase of developer activity in Q2. The root cause of this is unknown but will be investigated further.


Our goal is to grow and professionalise Zalandos open source efforts, to increase our community reach and thereby increase the pool of potential high-quality hires. To do so, we must have high quality open source offerings and dedicated maintainers.

The next 6 months, the Open Source team is focused on creating clearity of Zalando open source policies, remove barriers of entry and spread the culture of open source among current maintainers and new hires.

Single source of truth
Restructure and clearify process and policy documents to remove any uncertainty of Zalandos open source strategy
GitHub restructure
Focus on clear project ownership, compliant workflows and a simpler organisation of project maintainers
Onboarding program
Deliver open source onboarding program for all new tech hires
Increase our presence
Systematic approach to introducing new open source projects to the world and promote current initiatives and the teams behind them
Maintainer training
Project maintainer training on building community and being a great open source citizen
Policy and Rules Of Play
Align our policies to remove barriers and uncertainty. Work with legal, compliance and Zonar teams to improve our polices and legal contracts

Published By The Zalando Open Source Team

All the statistics mentioned in this report are collected through Roadblock