Remote Email Security Engineer — Open-Source Encryption

Our mission:

Are you a motivated Software Engineer looking to make an impact by strengthening digital security and sovereignty in the public sector in Germany?Europe’s digital infrastructure is evolving and we’re looking for people who want to help shape where it’s heading.
At Open-Xchange, 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 Open-Xchange 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 secure email solutions that strengthen digital sovereignty in Germany. As a Java Developer, you will enhance the encryption framework of OX App Suite, including PGP, S/MIME, and end-to-end encryption (E2EE). You will work closely with product, security, and UI colleagues to deliver a robust and user-friendly encryption experience.

Your new job:

• Maintain and improve existing backend and middleware components.
• Design and develop new services and APIs.
• Contribute to email encryption features (PGP, S/MIME, and end-to-end encryption).
• Collaborate with security and product colleagues to deliver reliable, user-friendly solutions.
• Support CI/CD pipelines, containerized deployments, and system operations.
• Write tests, review code, and document your work.

This is the tech stack you'll be working with:

• Programming languages and frameworks: Java, Spring Boot, OSGi
• Containerization and orchestration: Docker, Kubernetes, Helm
• CI/CD: GitLab CI, Jenkins
• Build tools: Gradle
• Databases: MariaDB/MySQL, Redis

Your background:

• Solid hands-on experience in software development, preferably in Java-based systems.
• Strong motivation and passion for working with the mentioned tech stack.
• Experience in secure communication technologies and cryptographic concepts (e.g. PGP, S/MIME, key handling, certificate chains, message signing).
• Experience with RESTful APIs, microservices, and distributed systems.
• Familiarity with end-to-end encryption concepts or architectures is a strong plus.
• Knowledge of email standards (SMTP, IMAP, MIME) is beneficial.
• Strong verbal and written communication skills in both German and English.
• Intrinsic motivation to take ownership and a passion for open-source technologies, thriving in a low-hierarchy environment.
• Comfortable working in a remote-first environment with multicultural teams across different time zones.

This is what you get at Open-Xchange:

• The flexibility to work 100% remotely ensures a work environment that suits you best.
• 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:

Join us in our fight for an open internet and deliver added value! Click “Apply now” to submit your application.

Your contact person:

Reach out to Justin ([email protected]) from the People Team. He will be able to discuss current opportunities and tell you more about our exciting vision and mission @OX.