Senior Backend Engineer (f/m/x) – API & Platform

Intro 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

Your mission

• 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

Your profile

• 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.

Why us?

• Shape the Future: Contribute to the energy transition by working on sustainable energy solutions in a growing market environment.
• Connecting & Co-Creating: Strategy off-sites and onsite weeks for real collaboration and shared ideas.
• Work Your Way: Home office and flexible hours – you know what works best for you and your team.
• Team Spirit: Yoga, shared lunches, after-work fun – we support each other and keep the vibe strong, even when it’s busy.
• Fair & Transparent: Clear structures, democratic decisions, and a feedback culture where your voice counts.
• Body & Mind: Urban Sports Club membership, wellbeing check-ins, and mental health support – your energy matters.
• New Office Vibes: 10th-floor office with rooftop terrace, canteen, great views, ergonomic desks, hardware of your choice, and pet-friendly!
• Sustainable Extras: Deutschlandticket, FutureBens, and more – supporting your mobility and future.

What else? A note on applications

As part of your application, we'd love to see a Python project you're genuinely proud of — production code, a side project, a study case, anything goes. It doesn't need to be polished. We'll use it as the basis for a technical conversation: what decisions did you make, why, what would you do differently? Send us the link of your repository. Be sure we have access.

If you don't have something ready to share, no problem — we'll send you a small, focused task instead.

Not quite senior level yet, but this role sounds like the direction you're heading? Apply anyway and let us know — we're also building out the junior side of the team.

We look forward to receiving your application, earliest start is as soon as possible. If you have any questions, feel free to reach out - your contact is Kathi (Interim Talent Partner).

You’ll hear back from us within 5 working days of your application. We value your time and want to make the process as transparent as possible. Once we receive your application, we’ll send you a confirmation email outlining the next steps and what you can expect from our interview process.

We can’t wait to meet you!

suena energy is an equal opportunity employer. We celebrate diversity and reject any form of discrimination. It is important to us to create an inclusive environment for all our team members. We want to particularly emphasize that our call for applicants is addressed to all genders. We welcome applications from people with disabilities.