About Thermosphr

Thermosphr is a ClimateTech startup optimising energy management for commercial buildings across Europe. Our software combines thermal modelling, model predictive control, AI, and real-time energy management — delivering over 30% energy savings for offices, shopping centres, and universities. Over 1 million square metres operated across Europe, with more than 3,000 tonnes of CO2 avoided to date.

We are an international team based in Paris and Berlin, in a phase of rapid growth. We value ownership, continuous learning, and close collaboration. This role offers direct, measurable impact on how we operate and scale.

What you'll do

You will work in close collaboration with the CTO, energy managers, customer success team, thermal and controls engineers, and building automation engineers to build and maintain the infrastructure underpinning our SaaS platform. Concretely, you will:

• Implement, maintain, and continuously improve a robust, scalable, and high-performance backend and cloud infrastructure
• Take full ownership of architecture and software development across the full cycle — from prototype to production
• Ensure stable and reliable real-time data flow between buildings and the cloud, including monitoring and alerting

What you bring

• C1 or C2-level English
• 6+ years of experience developing backend solutions in critical production environments
• Advanced programming skills in Python 3.12+
• 3+ years of experience with GCP or equivalent (AWS, Azure)
• Analytical and critical thinking; ability to take responsibility and ensure quality from prototype to production
• Fluency with AI-assisted coding tools (Claude Code and similar) — including the ability to critically evaluate AI-generated code and continuously improve internal procedures
• Comfort with a fast experimentation philosophy — you try often, fail fast, and learn quickly
• You stay current with developments in software engineering and security, with a genuine interest in producing battle-tested, production-grade code
• Entrepreneurial mindset — you find solutions, take initiative, and want to directly shape Thermosphr's product and direction

Bonus points

• Familiarity with MQTT and/or building automation
• Networking knowledge — routers, VLANs
• Ability to challenge existing architectures, including ones that have worked for years
• Fullstack development experience (any framework)
• Infrastructure as code with Terraform

Even if you don't tick all the boxes, we encourage you to apply.