FIXING THE PLANET BY MAKING HOMES CARBON-FREE! With €40 million in funding from top-tier investors such as COATUE, Foundamental & Target Global, we are working towards a future where climate-neutral buildings - simply & rapidly - become a reality. Through tailored solutions for millions of homeowners, we implement comprehensive energy-efficiency renovation projects, thereby establishing the infrastructure for climate-neutral living. As a Senior Backend Engineer, you’ll design and build the systems that power our platform — from customer-facing experiences to the data pipelines that drive automation, insights, and decision-making. You’ll work closely with product, design, frontend, and data teams to deliver reliable, scalable systems with real-world impact. Your mission Design, build, and maintain scalable, production-ready backend services Work across our platform — from customer-facing flows to internal systems and data pipelines Write and extend services primarily in Golang, TypeScript, and Python Drive architectural decisions, especially around our data core and automation pipelines Build and improve systems that transform customer data into actionable insights Ensure high code quality through testing, code reviews, and clean architecture Improve system reliability via CI/CD, monitoring, and alerting Collaborate closely with product and stakeholders to translate business needs into robust technical solutions Identify opportunities for product and operational improvements based on data and system insights Your profile 5 years of experience building backend systems in production environments Strong proficiency in Golang and solid experience with TypeScript and/or Python Experience designing and operating distributed systems and microservices architectures Strong understanding of event-driven systems (e.g. Kafka, NATS JetStream) Experience with cloud infrastructure (AWS or GCP) Hands-on experience with Docker and Kubernetes Familiarity with CI/CD tools (e.g. GitHub Actions, CircleCI, Terraform ) Experience with databases such as PostgreSQL, DynamoDB, MongoDB, or Cassandra Strong understanding of API design (REST, GraphQL) Comfortable contributing to frontend or user-facing components when needed to deliver end-to-end solutions Experience with monitoring and observability (e.g. Prometheus, Grafana, ELK) Solid understanding of performance optimization, caching, and database efficiency Experience with authentication/authorization (e.g. OAuth, FirebaseAuth) You write well-tested code and are comfortable with unit and end-to-end testing Full working proficiency in English (German is a plus) Benefits Become part of one of Europe's fastest growing Climate Tech Startups - funded by Europe's best known VC's Attractive & competitive compensation Work with top talent in a dynamic environment Individual benefits: learning budget, Urban Sports Clubs membership, job ticket or daycare allowance Office with a direct view of the Spree River, with everything your heart desires Numerous team events, including yoga About us We believe in open and transparent communication and work on an equal footing with short decision-making processes. Passion, ambition, optimism and transparency drive us every day!