UI Developer

• Develop and improve user interfaces using JavaScript and TypeScript, with a focus on our solutions for the public sector.
• Take ownership across the full development lifecycle, from architecture and implementation to testing, quality assurance, and deployment.
• Build and maintain a distributed, cloud-native platform running on Kubernetes and serving millions of users across customer environments and our own cloud infrastructure.
• Contribute to high software quality through CI/CD, automated testing, code reviews, and continuous improvements to our development processes.
• Use modern developer tooling, including agentic coding and AI-assisted development, as part of your day-to-day work.
• Build software with long-term maintainability in mind and help continuously improve our codebase and technical architecture.

• Master’s degree in Computer Science, Software Engineering, or a related field.
• Multiple years (5+) of professional development experience at a senior level, with the ability to take ownership of features from concept to production.
• Strong knowledge of JavaScript and modern web architectures.
• Passion for designing intuitive APIs and user interfaces with a strong focus on usability.
• Experience with CI/CD pipelines and automated testing.
• Ability to communicate technical concepts clearly, contribute ideas, and collaborate effectively within a development team.
• Fluent German and good English communication skills.

Nice to Have

• Experience with Vue.js, particularly its reactivity system.
• A strong eye for UI design and user experience (UX), combined with an understanding of accessibility standards and inclusive UI design.
• Experience with microservices, Kubernetes, container technologies, and cloud-native architectures, as well as relational databases such as MariaDB and Galera Clusters.
• Knowledge of the email and calendar domains, including relevant protocols and standards such as IMAP, RFC 822, CalDAV, iMIP, and iCalendar.

• Flexible working hours that allow you to successfully combine your home and family responsibilities with work.
• Getting together in-person for workshops and fun team events.
• Time off to volunteer - and mental health support when you need it.
• We provide financial relief through corporate benefits and a subsidy for ergonomic chairs and desks.
• We can discuss further location-related benefits together in an initial talk.

Join the team

Open-Xchange Olpe, 57462 Unbefristet Teilzeit Our mission:

Are you an experienced UI developer who wants to build software that makes a real difference? Join us in creating modern, user-friendly solutions for the public sector while working with open technologies and taking ownership from development to deployment. Europe’s digital infrastructure is evolving and we’re looking for people who want to help shape where it’s heading. At Open-Xchange (OX), we develop open-source communication and collaboration software used by public sector organizations, telcos, and hosting providers to keep data secure and under their control. Our products cover email, collaboration, DNS security, and related services, and are used by millions of people worldwide. Discover what OX offers you:

• We work in a non-hierarchical organization that empowers everyone to take responsibility, stay focused, and contribute directly to the company’s success and customer value.
• We value expertise and continuous professional development. Our professionals work closely with experienced colleagues, take ownership of their work, and continuously expand their skills.
• Openness and diversity are core to OX. Different perspectives, backgrounds, and ways of thinking strengthen our collaboration and help us see the bigger picture.

Your team:

As part of the cross-functional OX Public Sector team, you will help develop modern email and calendar solutions that are specifically tailored to the requirements of public administration. In doing so, you will actively contribute to strengthen the digital sovereignty of the public sector in Germany. Your new job