Les missions du poste At Flexcity, we help the European power system become smarter, more flexible and more sustainable by connecting industrial assets (batteries, e-boilers, heat pumps, data centers...) to energy markets. A subsidiary of Veolia Group, we combine scale-up agility with the stability of a global leader. At Flexcity, tech is a business driver, powering optimization and financial performance across Europe. As a Senior Backend Developer F/H/X in the Strategy team, you will build the systems that optimize asset behavior and maximize €/MWh value through fully automated decision-making. The team works at the intersection of backend engineering and data science, powering forecasting models, MILP optimizers, simulations and large-scale historical data pipelines. Your work directly improves financial outcomes for clients and Flexcity. You will work end-to-end with a Product Manager and Engineering Manager in a high-autonomy feature team. Your role focuses on: - Backend Development (80%) - Build backend services powering optimization, forecasting and decision engines. - Design scalable pipelines handling large datasets and computational workloads. - Own features from design to production monitoring. - Team & Engineering Improvement (10%) - Improve engineering standards, workflows and technical quality. - Contribute to a strong culture of craftsmanship and continuous improvement. - Technical Leadership (10%) - Partner with Product Managers on feasibility, scope and trade-offs. - Ensure architectural consistency and long-term system quality. Le profil recherché You are a senior backend engineer with 15+ years of experience building scalable systems, ideally in data-intensive, optimization-driven or algorithm-heavy environments.Technical Knowledge & SkillsStrong backend engineering and system design expertise.Experience with or strong interest in distributed systems, data pipelines or optimization engines.Comfort working on complex, computation-heavy production sy