Kotlin developer Jobs in Berlin

What You'll Do

We are looking for a (Senior) Backend Developer who takes ownership and thinks about backend systems from initial concept through to production. Whether you’re building robust APIs, designing high-performance database architectures, or integrating AI solutions, your hands-on mindset and technical judgment make the difference.

You will work closely with frontend, product, and AI teams and play an active role in shaping our technical future.

As a (Senior) Backend Developer (m/f/d), you will be responsible for:

• Designing and implementing scalable server-side architectures and database models
• Developing, maintaining, and evolving high-performance, secure, and maintainable backend services
• Owning API design, versioning, and lifecycle management
• Collaborating closely with frontend teams to integrate user-centric features
• Building and operating scalable infrastructure for AI workloads and external API integrations
• Ensuring high software quality through automated testing (unit, integration, and end-to-end)
• Actively monitoring and evaluating new technologies and architectural trends

What you bring

Hard Skills

• Several years of experience as a (Senior) Backend Developer
• Strong proficiency in Kotlin, Java, or another JVM-based language
• Solid understanding of modern backend development principles and architectures
• Hands-on experience with LLM integrations (e.g. OpenAI, Anthropic, or comparable APIs)
• Experience working with vector databases (Pinecone, Weaviate, Qdrant) for RAG implementations
• Understanding of prompt engineering, context management, and AI orchestration frameworks (e.g. LangChain, LangGraph)
• Experience with message brokers and queueing systems (e.g. RabbitMQ or similar) is a plus
• Experience with Micronaut, MySQL, AWS, and Kubernetes is an advantage, but not a requirement
• Business-fluent English and good German language skills

• Openness, courage, and a creative, solution-oriented mindset
• Clear communication and strong alignment with both team and product stakeholders
• High sense of ownership and strong quality awareness
• Enjoyment of working collaboratively in a fast-paced, dynamic environment

What we promise

Work Environment & Flexibility

• Office-first company: Hybrid setup with 3 days in the office and 2 days working from home, offering flexibility in how you structure your work
• Modern, air-conditioned office with plenty of natural daylight
• Central location between Gleisdreieck and Potsdamer Platz with excellent public transport access
• Spacious rooftop terrace with stunning views over Berlin

• Full coverage of a Germany-wide public transport ticket
• Dog-friendly office – we’re happy to welcome four-legged team members
• Corporate benefits platform with attractive offers and discounts across many brands
• Company pension scheme with a 20% employer contribution – we invest in your future
• Regular company and team events to strengthen collaboration and team spirit
• After-work fun: Nintendo Switch, PS5, darts, and table football
• Free drinks, fresh fruit, and muesli available at all times

• Agile and modern mindset with open communication – every voice is heard
• Meaningful areas of responsibility with a strong focus on practical, real-world legal solutions
• The opportunity to actively shape our journey and contribute from day one
• Feedback is part of our culture – we believe in continuous, shared growth

• Fast feedback
• 1. Approx. 20-minute introductory call with our HR team
• 2. Approx. 60-minute on-site interview with your hiring manager
• 3. Approx. 30-minute meeting with the management team
• A prompt offer following the interview process

About us

Legalhero is the modern platform for legal protection insurance and lawyers. We pursue the ambitious goal of revolutionizing the claims settlement process for legal protection insurance. To this end, we integrate directly into the insurers' systems. Our partner lawyers handle cases highly efficiently and in a customer-oriented manner on our tech platform with the help of AI. Legalhero was founded in 2017 and has helped hundreds of thousands of policyholders to date. Our approximately 90 colleagues are based in Berlin, near the Gleisdreieck.

An inclusive, equal, and non-discriminatory work environment is a matter of course for us. If you have a disability or special needs and require special support during the application process, please let us know.