Senior Backend Engineer

The Germany-based team serves as the company's software and digital solutions hub, developing platforms that enable customers to analyze, manage, and extract valuable insights from complex battery data. By combining expertise in battery science with modern software engineering, the company helps customers accelerate innovation, improve product performance, and make informed technical and business decisions. With customers across Europe, North America, and Asia, this company is experiencing continued growth driven by the increasing demand for battery technologies, electrification, and data-driven development solutions., We're building a high-impact SaaS platform at the intersection of Battery Design, Development, and Production and software, focused on solving real-world problems in the battery ecosystem. We're looking for a Senior Backend Engineer to take ownership of our backend systems -from architecture to production. You'll work on systems that ingest, process, and serve complex data, and help shape a platform that customers rely on for critical decision-making. This is a high-ownership, hands-on role for someone who thrives in ambiguity, makes strong technical decisions, and ships reliable systems quickly without sacrificing quality. Experience in the battery sector and practical AI integration is a strong plus., Design and build scalable, resilient backend systems using Node.js (NestJS) and Python (FastAPI). Own API design and service architecture, balancing performance, maintainability, and developer experience Develop and evolve data models and pipelines for complex, real-world datasets (including battery-related data) Build and maintain multi-service, cloud-native systems on AWS Improve system observability, reliability, and incident response practices Drive CI/CD, infrastructure-as-code (Terraform), and secure deployment workflows Collaborate closely with product and frontend teams to deliver end-to-end features Make pragmatic decisions - knowing when to move fast and when to invest in long-term architecture Contribute to a culture of high-quality engineering through code reviews, testing, and continuous improvement, Backend: Node.js (NestJS), Python (FastAPI) Frontend: React.js (Hooks, Context, modern state management, component libraries) Databases: PostgreSQL, Redis, NoSQL Infrastructure: AWS, Docker, Terraform, GitHub Actions Attractive Points Work on real-world energy problems with tangible impact Own systems end-to-end Influence architecture, product, and technical direction Build from first principles in a fast, execution-focused team High autonomy, low bureaucracy, and meaningful responsibility

Mandatory Qualifications (All must be met): 5+ years of experience building and operating production backend systems Strong proficiency in Python and Node.js (experience with NestJS or FastAPI is a big plus) Deep understanding of:

• API design (REST, service boundaries, versioning)

• Distributed systems and microservices tradeoffs

• Data modeling and database performance Proven experience building SaaS platforms or complex backend systems Hands-on experience with:

• AWS (or similar cloud platforms)

• Docker and containerized environments

• CI/CD pipelines and infrastructure-as-code Strong experience with PostgreSQL and/or NoSQL databases Ability to debug and resolve complex production issues Comfortable working in a fast-moving, startup environment Strong Plus Experience in the battery domain Experience building data-intensive or real-time systems Exposure to AI/ML systems, LLM integrations, or AI-powered features Experience designing event-driven architectures Proven experience in team management and driving technical best practices across backend teams.

Salary Range: €60,000-€80,000 gross per annum Work Style: 100% onsite in Stuttgart office Team Environment: Agile, collaborative, and high-ownership culture Career Growth: Clear path toward leadership or specialist roles Learning & Development: Direct access to founders and product teams

This company is an innovative technology business operating at the intersection of advanced battery technology and software development. It supports customers throughout the battery lifecycle, from research and development to production readiness and data-driven optimization.