Hamburg Hybrid (2–3 days/week onsite) | 70.000 - 85.000 € p.a. (40 hrs / full time) | 30 Days Vacation | English B2 | German C1 Are you passionate about building the technical backbone of the energy transition? Join suena energy as Senior Backend Engineer (f/m/x) and become a founding member of our newly formed Platform team. You'll help design and build the API and integration layer that connects our trading, analytics, and optimization systems — and in doing so, directly shape how clean energy is managed across European power markets. suena energy is a green tech startup specializing in algorithmic energy trading for battery storage systems and renewables. Our vision: a world where clean energy is used reliably, economically, and intelligently. With our AI-based optimization and trading software, we maximize the revenues of operators of large-scale energy storage and renewable assets on short-term electricity and balancing markets - while simultaneously minimizing their risks. We're a team of 50+ people, combining a warm, supportive culture with real startup drive. Following our successful Series A, we're now building a dedicated Platform team from scratch. Quick Check: Is this your kind of engineering challenge? Tech Stack: Python (Django/FastAPI), PostgreSQL/TimescaleDB, Redis, Celery, Docker, AWS, GitLab CI/CD, Sentry, Grafana Your Focus: API design & architecture, backend integrations, data flows, system reliability and scalability Team: Small, newly formed platform squad — you'll work closely with the Platform Lead, with strong support from our CTO in the early phase Product: Real-time energy trading platform — high complexity, data-heavy, ML-integrated Who thrives here: Engineers who think in systems, take ownership, and are energized by building things that actually matter Must-haves: 5+ years backend experience, solid API & architecture background, Python, cloud deployment, German C1 Dealbreakers: No API/architecture experience, pure CRUD background, no interest in complex distributed systems Design and build scalable, reliable APIs and backend integrations that connect trading, analytics, data science, and forecasting systems Drive the architecture of suena's platform layer — from initial design decisions to production Own data flows and backend automations across the platform Collaborate closely with the Platform Lead, CTO, and cross-functional teams (trading, data science, modelling) to translate complex domain requirements into robust technical solutions Improve and extend existing systems while keeping a clear eye on reliability, security, and performance Contribute to technical standards, code reviews, and engineering practices as the team grows 5+ years of backend engineering experience, with a strong focus on API design and system architecture Solid Python skills (Django and/or FastAPI); hands-on experience with PostgreSQL/TimescaleDB is a plus Experience with distributed/cloud-based architectures (AWS preferred), Docker, CI/CD, async workflows (Celery, Redis) You think beyond the ticket — you understand how systems connect and can make principled architecture decisions Security-minded: authentication, authorization, zero-downtime deployments are familiar territory Comfortable working across greenfield projects and legacy systems German C1 is required for this role — we work closely with German-speaking external API partners and system integrators, and clear, direct communication in German is essential for this English B2/C1 for internal collaboration Nice to have: Experience or genuine curiosity about energy markets, trading systems, or related domains (finance, IoT). The domain is complex — enthusiasm to learn it matters.