Senior Backend (Java) Engineer - Trust and Safety (d/f/m)

Kleinanzeigen is the leading online classifieds market in Germany. Users buy and sell on Germany's No. 1 for classifieds mainly second-hand. In this way they make an active contribution to more sustainability. On average, more than 55 million ads are available in numerous categories – from children's supplies to electronics and real estate. Kleinanzeigen also offers small and medium-sized businesses the opportunity to present their services online. Around 35 million users per month make Kleinanzeigen one of the most widely used websites in Germany. Kleinanzeigen was launched in September 2009 as eBay Kleinanzeigen. Since June 2021, the company has been part of Adevinta, a global provider of online classified ads. In May 2023, the name was changed to Kleinanzeigen.

We are looking for a professional individual to join our team as a Senior Backend 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.  

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

• 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.

Your role:

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

• 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 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)

• 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

• Confidential support & coaching for you and your loved ones

• Annual company sports events

• Pension and life insurance

 Growth & Development

• Personal development budget

• Learning opportunities to grow your skills and career

 Perks & Everyday benefits

• Corporate benefits and exclusive discounts

• An attractive referral program 

• Transportation allowance

• Free shipping on Kleinanzeigen Direktkauf

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.