Senior Python Backend Engineer

🚀 Senior Backend Python Engineer Location: Hybrid in Berlin, Germany (2 days in-office) Salary: €80-120k + Equity Language: English speaking Start Date: ASAP Full time: 40 hours per week 🌟 The Company Do you want to build the infrastructure that powers Europe's transition to renewable energy? Then apply today! Our client is a fast-growing ClimateTech scale-up dedicated to optimizing smart grids and distributed energy resources. Using real-time data and machine learning, they help energy providers reduce carbon emissions, prevent grid overloads, and integrate renewable sources efficiently. They are a dynamic, international team of experts operating in a high-growth environment. Backed by top-tier European climate and tech venture funds, they offer the agility and excitement of a startup combined with a sustainable, long-term mission and solid financial runway. 💡 The Project As a Senior Backend Python Engineer, you will join immediately to architect and scale their core energy data processing pipeline and real-time API orchestration layer. This is a heavy systems-design role where you will not only write performant, asynchronous Python code but also shape the microservices architecture that handles millions of IoT data points daily. You will collaborate closely with Data Scientists, DevOps, and Product teams to build highly scalable backend systems using Python (FastAPI), Kafka, and PostgreSQL, ensuring machine learning models are successfully integrated into production. If you are a builder who values scalable architecture and wants to use your technical skills to fight climate change, then this is the role for you! 🎯 Responsibilities Architect & Scale: Design and implement high-performance, distributed backend services that process massive volumes of real-time sensor and grid data.Build & Ship: Write clean, reliable, and asynchronous code in Python using modern frameworks like FastAPI.Collaboration: Work closely with the Data Science team to productionize machine learning models and integrate them into the core product API.Data Pipelines: Optimize and manage data streaming architectures and relational databases to ensure low latency and high availability.Quality Assurance: Champion best practices in code reviews, automated testing, and CI/CD workflows to maintain a highly robust production environment. 💻 Tech Stack Backend: Python (FastAPI).Data & Messaging: PostgreSQL, Apache Kafka, Redis.Cloud & DevOps: AWS, Docker, Kubernetes, GitHub Actions.Testing: Pytest, mock frameworks. 🛠️ Your Experience 5+ years of professional software engineering experience.Deep Python Expertise: Extensive production experience building complex backend systems and RESTful/GraphQL APIs using modern Python.Distributed Systems: Hands-on experience with microservices architecture, asynchronous programming, and event-driven systems (Kafka, RabbitMQ, or similar).Database Mastery: Strong background in relational databases (PostgreSQL), complex query optimization, and schema design for time-series or heavy data loads.Cloud Native: Experience deploying and managing applications in containerized environments (Docker, Kubernetes) on AWS or GCP.Testing: Proven track record of ensuring high software quality through rigorous automated testing (Pytest) and clean architecture principles. 🧬 You will be a cultural fit if... You have a High-Ownership Mindset: Autonomous, proactive, and taking full responsibility for the systems you build from local development to production.You are a Critical Thinker: Someone who is not afraid to speak up, constructively challenge architectural decisions, and provide scalable solutions.You are Collaborative: Structured, goal-oriented, and enjoy mentoring junior engineers while working cross-functionally.You bring Enthusiasm: A strong passion for sustainability and a positive attitude toward solving hard technical problems. 🎁 Benefits Competitive salary + generous stock options package.Flexible working hours and a hybrid working model with a beautiful, dog-friendly office in the heart of Berlin.Choice of premium hardware (MacBook Pro or Linux machine).Annual learning & development budget of €2,000 for conferences and courses.Urban Sports Club membership and public transport subsidy (BVG ticket).30 days of paid holiday.A role with both deep technical challenges and a mission that genuinely impacts the planet. 📝 Interview Process 1st. Intro Call: Background & Culture check with the internal Tech Recruiter (30 mins). 2nd. Technical Session (90 mins): Systems Design & Architecture: A collaborative session focusing on scaling a data pipeline and backend architecture. Live Pairing: Writing and refactoring clean Python code together (practical problems, no algorithmic Leetcode tricks). 3rd. Team Interview: Meet a Data Scientist, DevOps Engineer, and Product Manager from the team → cultural fit, cross-functional collaboration, and communication. 4th. Final Stage: Virtual or in-office meeting with the CTO / Founders to discuss long-term vision, engineering mindset, and mutual alignment. Offer!