Lead Full Stack Developer
Thermosphr is a fast-growing European Climate Tech company combining AI, advanced engineering and energy optimization to make large commercial buildings significantly more efficient. Our AI autopilot connects to existing heating and cooling systems, reducing energy consumption by 20 to 30%.
We work with leading European real estate owners and asset managers, with our technology already deployed across around 100 buildings and over 2 million m². We operate across Europe, with entities in France, Germany and Poland.
We're entering a new phase of growth, with ambitious plans to accelerate commercial expansion, scale our organization and broaden our offering.
Our ambition is to make autonomous energy optimization the new standard across European commercial real estate.
What you'll do
Our software doesn't just display data. It makes decisions and controls real equipment, in real buildings, every day.
Thousands of data points flow continuously between connected buildings, our cloud infrastructure and our AI optimization algorithms. Making this work reliably and at scale is a fascinating engineering challenge. But we're equally ambitious about building an outstanding software product, with intuitive interfaces and a great user experience.
We're looking for a hands-on technical leader to take our software platform, product experience and engineering team to the next level.
Working directly with our CTO and closely with our CEO, Sales, Operations and other teams, you'll combine technical leadership with strong product and business ownership. Expect roughly 60% hands-on development and 40% technical leadership, design and coordination.
Your responsibilities will include:
Connect technology with business priorities. Understand challenges across the company, identify opportunities and translate them into an actionable technical roadmap. Challenge requirements, set priorities and make smart trade-offs to maximize business impact.
Build an outstanding product experience. Work closely with users, understand their workflows, challenge existing UI/UX choices and develop intuitive, powerful interfaces that make our technology a pleasure to use.
Build and scale our platform. Design and develop software across the stack, from frontend applications to backend services, APIs, data flows and cloud infrastructure. Shape our architecture and ensure reliability, security and scalability.
Turn ideas into results. Drive projects from concept to production and adoption, balancing speed, quality and pragmatism. Your success will be measured by the value your solutions create, not simply the features you deliver.
Lead and grow our engineering team. Provide technical direction, mentor colleagues, improve engineering practices and foster a collaborative culture where developers understand the impact of their work.
You'll have genuine ownership, direct access to decision-makers and the freedom to challenge existing approaches and shape how we build technology at Thermosphr.
Who you areWe're looking for an excellent engineer who loves building great products, understands the business behind them and enjoys helping others achieve outstanding results.
You're an engineer at heart. You take pride in building robust, elegant software, enjoy solving complex technical problems and know when to prioritize pragmatism over perfection.
You think product and business. You care about users, have an eye for great UX and understand that technology serves business objectives. You challenge what to build, not just how to build it.
You take ownership and deliver. You're autonomous, resourceful and comfortable making decisions, even with incomplete information. You get things done and take responsibility for the results.
You make others better. You communicate clearly, enjoy working with technical and non-technical colleagues, challenge ideas constructively and inspire others through your expertise and attitude.
What you bring:
Ideally 7+ years of software engineering experience, including technical leadership or ownership of major software components.
Excellent Python skills and strong JavaScript / TypeScript experience with modern frontend frameworks.
Solid expertise in backend architectures, APIs, databases, cloud infrastructure and distributed systems.
Hands-on experience with GCP, AWS or Azure, CI/CD, automated testing and production operations.
Experience translating business and user needs into technical solutions, with a good understanding of UI/UX and product development.
Familiarity with AI development tools and how to use them effectively.
Excellent communication skills and professional fluency in English.
Nice to have: Experience with IoT, MQTT, industrial systems, Infrastructure as Code (Terraform), event-driven architectures or time-series data.
You don't need to know anything about HVAC or commercial buildings. What matters is your engineering expertise, curiosity, product mindset and ability to learn fast.
The team & working environmentYou'll report directly to our CTO and lead a small, international team of experienced software engineers, working closely with colleagues across our European offices.
We're based in central Paris, with a hybrid working arrangement.
Our organization is lean, giving you significant influence over technical decisions, product priorities and how our engineering team evolves.
If you want to shape a growing technology platform, build a product people love using, lead great engineers and still spend most of your time coding, we'd love to hear from you.
We're committed to making the recruitment process as fast and transparent as possible. It goes as follows:
A first phone call with our CTO, Aaron • 10-15 min
Tech Interview with Sylvain or Tim • 1-1.5 hour
Interview on culture fit or tech interview • 1 hour
Final interview with our CEO, Nico • 1 hour