Principal Engineer (d/f/m)

mobile.de is Germany’s largest vehicle marketplace, with more than 1.6 million listed cars, commercial vehicles, motorcycles, and e-bikes (annual average 2025). Both private customers and registered vehicle dealers use the platform and benefit from more than 140 million visits per month*. As a “one-stop shop,” mobile.de’s offering includes not only buying and selling, but also financing and leasing solutions. Founded in 1996, the company is a subsidiary of Adevinta, a global leader in online classified portals. Based in Berlin-Charlottenburg, we offer a dynamic environment where growth, learning, and collaboration are at the heart of everything we do. If you are driven by an eagerness to disrupt, have a passion for collaboration, and are excited about shaping the future of mobility, we would love to hear from you. About the Role This role is embedded in the Consumer Orientation & Specification (COS) cluster, one of mobile.de's three core Product & Tech (P&T) clusters. We are looking for a hands-on Principal Engineer to provide technical leadership across our Consumer engineering organization. This is a senior individual contributor role for someone who combines deep technical expertise with strong collaboration, communication, and mentoring skills. You will work closely with Tech Leads, engineers, product, QA, and data stakeholders - including external contractor teams - to improve alignment, reduce duplication, and enable teams to build scalable, maintainable, and high-quality solutions. As the majority of our Consumer traffic comes from our Native Apps, a solid understanding of Native engineering and mobile-first thinking is important in this role. You are someone who doesn't just keep up with AI — you lead by example, making AI tooling a natural part of how you and your teams work. And when it comes to aligning people around a technical direction, your communication and storytelling skills are just as sharp as your engineering instincts. Collaboration & Community As a Principal Engineer, you are the key connection between the Consumer engineering organization and the Platform Team, acting as a multiplier by translating platform direction into actionable guidance for the Consumer Area's Tech Leads. You actively build and nurture a technical community among those Tech Leads, while staying closely connected to fellow Principal Engineers across mobile.de. Together, this group of senior technical leaders drives alignment on guidelines, architectural decisions, and the Tech Radar — ensuring that technical direction is consistent, well-communicated, and grounded in a shared understanding of mobile.de's system landscape. Extensive hands-on experience in software engineering, with a proven track record at senior or principal level Experience working on high-volume traffic platforms Interest in Native App development, including its ways of working and software delivery processes Ability to design and evolve architectures for complex, large-scale software systems, with a strong sense of strategic and system-level thinking Experience with scalable distributed systems, APIs, and end-to-end system design Strong understanding of QA practices, observability, operational excellence, and cost-aware engineering (FinOps) to demonstrate end-to-end ownership, from development through to operations Experience collaborating closely with data teams or working on data-intensive systems Excellent communication and storytelling skills, with the ability to manage stakeholders and influence and align across teams and functions without direct authority Drives decisions by informed consent — ensuring the best technical argument wins, and committing decisively once a direction is set Experience providing technical guidance and mentoring to Tech Leads or senior engineers Participation in or leadership of cross-team technical communities such as a Community of Practice Active user of AI coding and productivity tools, with a growth mindset towards further AI adoption Fluent English; German is a nice-to-have given our Berlin office context Lead and align Consumer Area-wide architectural decisions, enabling teams to make sound technical decisions that satisfy business and functional needs Define, share, and own Technical Excellence goals within the Consumer Area Continuously assess technical debt and drive solutions at Consumer Area level Provide technical guidance and mentoring to Tech Leads in the Consumer Area, and support performance feedback Support teams with hands-on software development where needed due to complexity Proactively identify opportunities where AI tools can improve or completely redesign engineering processes to make them faster and better Champion responsible AI adoption within the Consumer Area, including human-in-the-loop practices, AI output validation, awareness of ethical considerations, EU AI Act compliance, and FinOps/ROI thinking Drive Native App technical & delivery excellence within and beyond the Consumer Area, understanding that Consumer feedback is key to success What success looks like Teams are well aligned on architecture, quality, and technical direction and can execute smoothly within these guardrails Cross-team collaboration improves and duplicated solutions are reduced to a minimum. Tech Leads and senior engineers feel supported and enabled. Technical risks, dependencies, and bottlenecks are surfaced early and addressed effectively. Engineering quality and maintainability improve across the organization. AI-related initiatives are approached pragmatically and integrated thoughtfully into the broader technical landscape. Tech stack Languages: Java, TypeScript, Python Mobile/Native: iOS (Swift/SwiftUI, Core ML), Android (Kotlin, Jetpack Compose, ML Kit) (nice to have) Web: React, Next.js, TypeScript/Node.js AI: Claude (or equivalent), SDD, AWS AgentCore Search & Data: ElasticSearch, Kafka, MongoDB or similar for search-driven and data-intensive systems APIs: REST, MCP Infra: Kubernetes, Docker, cloud services (AWS/GCP) CI/CD: GitHub Actions, test automation Observability: OpenTelemetry, Prometheus/Grafana, ELK, Firebase We don't expect you to know all of these — we value curiosity and the ability to learn. Working at mobile.de comes with its perks! Enjoy the following benefits (some of many): • Rewards: competitive base salary and participation in the company’s incentive programs. • Plan for the Future: On top of the statutory retirement insurance, we offer a competitive company pension scheme. • Team-Building: Regular team and company events offer the opportunity to network and learn from each other. • Learning & Development: Keep growing with access to coaching, learning platforms and resources. • Mobility: Stay mobile with a monthly transportation allowance. • Enjoy working: Our well-equipped office supports focused work and teamwork – plus inviting social zones where colleagues can relax and connect. • Flexible working: a hybrid approach with the option to work abroad for a set number of days per year. • Wellbeing: confidential employee assistance and support services available to employees and their immediate families. • Family support: enhanced parental leave and family-friendly policies to support all parents and careers. Meaningful Work: We are a diverse, international, highly skilled and passionate team committed to a world where people share more and waste less. Every day you will have the opportunity to make a huge difference for our users, customers as well as shape the future. Embracing AI: We’re at the forefront of integrating cutting-edge AI technologies into our operations. Being part of mobile.de you will work with and learn about AI tools, contributing to projects that leverage AI to enhance efficiency, improve customer experiences, and drive our mission forward. With an AI-first mindset, we foster a culture of continuous learning and experimentation, empowering our team to explore and apply AI in meaningful ways for the company and themselves. Connection and Inclusion: Our culture is the glue that holds us together. We believe in making meaningful connections and creating an inclusive atmosphere with lots of opportunities to connect both in your day to day work and through social team activities (online and offline). mobile.de is an equal opportunity employer and we value diversity. We do not discriminate on the basis of race, religion, color, national origin, gender, sexual orientation, age, marital status or disability status.