Senior Full Stack (Java) Engineer

Kleinanzeigen is the most-visited general classifieds site in Germany and is still growing at an amazing speed. We have over 50 million items for sale on our platform, and with more than 35 million unique users every month, we reach about 50% of the German internet population. Are you passionate about joining a purpose driven community that is dedicated to building an ambitious and diverse work environment? Join Kleinanzeigen!

We are looking for a professional individual to join our team as a Senior Full Stack Engineer (d/f/m). In this role, you will be responsible for developing services for our trust and safety domain to prevent fraud and safeguard our users. You will be part of a cross-functional team including members from the areas of Product, Customer Service, Analytics and Engineering with the mission "to make our platform a safer place to trade”. This is your opportunity to improve the experience of millions of users and have an impact by building a platform that enables sustainable trade for everyone.Your role:

• Own backend and frontend services end-to-end: design, build, operate, and continuously improve systems in the Trust & Safety domain

• Deliver user-facing features across the full stack — from Java/Spring services to Astro-based server-rendered micro-frontends and widgets — deployed independently to production.

• Design scalable and resilient systems capable of handling high traffic (up to 60k requests per second).

• Drive complex feature development and architecture evolution from problem definition to production, making and clearly justifying trade-offs between performance, scalability, and cost.

• Collaborate closely with Product and Design to shape and deliver solutions for a safer and trusted kleinanzeigen.de platform

• Raise engineering standards by contributing to code reviews, product ideas, improving testing strategies, and evolving development processes and conventions.

• Ensure system reliability by implementing effective monitoring, alerting, and incident handling practices.

• Leverage modern engineering practices and AI-assisted tools to improve developer productivity and delivery quality.

• At least 6+ years of programming experience in Java backend development with strong knowledge of Java Core APIs, Spring Framework and Spring Boot, TypeScript and React.

• Proven experience designing and operating robust, scalable distributed systems. Ideally on public clouds (e.g. AWS with k8s)

• Solid understanding of system design, architectural trade-offs, and evolving existing systems

• Strong knowledge of event-driven systems (e.g. Kafka)

• Experience with RDBMS and NoSQL (preferrably MySQL, Cassandra, Elasticsearch)

• Strong engineering fundamentals, including Domain-Driven Design and Clean Code practices.

• Willingness to participate in out-of-office on-call rotations as part of owning production systems is required.

• Experience mentoring engineers and contributing to team growth through knowledge sharing

• Familiarity with AI-assisted development tools and an understanding of their trade-offs (e.g. quality, security, cost)

• You have a speak up mentality and point out things that are not right in your opinion.

At Kleinanzeigen, we care about our people — their wellbeing, growth, and life beyond work. Our benefits are designed to support you holistically, giving you flexibility and opportunities to thrive.

✨ Flexibility

• Flexible working time (hybrid)

• 26 days of holidays

• 20 days “work from anywhere”

• Paid additional parental leave for both parents

• Extra paid days off for special occasions (e.g. your wedding or a move)

❤️‍? Wellbeing & Support

• Private health insurance

• Gym Pass (may cover up to 70% of gym membership fees)

? Growth & Development

• Personal development budget

• Learning opportunities to grow your skills and career

?️ Perks & Everyday benefits

• Corporate benefits

• An attractive referral program

Kleinanzeigen is an equal opportunity employer that values diversity and inclusion. We welcome people of all backgrounds, races, religions, colours, national origins, gender identities, sexual orientation, ages, marital status, or disability.

If this role sparks your interest but you’re not sure you meet every single requirement, we’d still love to hear from you anyway.