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CarOnSale is an AI-powered operating system for B2B used car trading in Europe, connecting 40,000+ buyers across 20+ countries and processing 130,000 vehicle sales annually through its auction backend platform. The company integrates software, pricing intelligence, logistics, and financing into a unified layer serving the automotive trading industry.
In this Senior Backend Engineer role, you will own backend development end-to-end: technology selection, architecture design, and implementation of features that drive platform performance and scale. You'll work with TypeScript, Node.js, NestJS, and PostgreSQL to build systems handling massive transaction volumes. The role emphasizes an AI-first approach—coding agents, LLMs, and AI-assisted development are embedded in daily workflows, not experimental pilots.
Key responsibilities include setting engineering standards (code quality benchmarks, development practices, CI/CD pipelines) across the team, mentoring engineers to raise backend practice standards, and challenging existing approaches with better solutions. You'll have autonomy over architectural decisions and technology choices rather than executing tickets designed by others.
Required qualifications: 8+ years software engineering experience with 5+ years focused on backend development. Deep TypeScript proficiency with strong Node.js, NestJS, and PostgreSQL expertise. Proven mentorship track record. Solid Git, Docker, and CI/CD pipeline command. Comfortable with Scrum/Kanban, JIRA, and Confluence. C1-level English for international team collaboration. AI-native working style with practical judgment on tool application. Based in Berlin or willing to relocate.
Nice-to-have skills include WebSockets/real-time systems, search frameworks (Elasticsearch, Lucene), and automotive or B2B trading background. The role is hybrid (3 days office, 2 days remote) based in Berlin-Schöneberg.
