Senior Fullstack Developer - Optimization Team (m/w/d) Green-Tech Start Up

Digitalization and the energy transition in one sentence? Yes – at Green Fusion!

Our software optimizes the control of heating systems in residential buildings, helping to fight climate change. By digitalizing and automating control processes, we reduce both emissions and energy consumption – actively driving forward the energy transition.

As a Senior Fullstack Developer, you’ll join our cross-functional Optimization Team and help bring our product vision to life:

"Emitting less, gaining more: Transform residential buildings into auto-optimising, CO₂-neutral assets."

You'll play a key role in writing software to improve our end-to-end optimization of heating systems in close collaboration with energy data scientists, system engineers, designers and product managers.

• Collaborate with your team to understand underlying problems and requirements.
• Engineer requirements into viable, pragmatic software designs.
• Contribute to team planning by helping define tasks, priorities, and timelines.
• Write Software – implement end-to-end, from database model to frontend.

• Solid educational background – ideally a degree in Computer Science or a related field
• 5+ years of professional experience in software development
• Solid experience across frontend and backend – especially with TypeScript, Next.js, SQL
• Familiarity with Python, Nest.js or systems engineering is a plus
• Ability to write high-quality, production-ready code and streamlined APIs
• Strong communication and collaboration skills to take on responsibility and work closely with other engineers
• Independent, structured working style
• Fluent in English

💼 Employee perks like Urban Sports Club or Become1 membership.

🏠 Flexible working hours and remote work – continue working from home even post-pandemic.

💡 Continuous learning – through on-the-job challenges, an open feedback culture, and supported professional development.

🌱 Real impact – contribute directly to the energy transition and help fight climate change every single day.

💚 Team appreciation – we value our team, which is why regular team events are an essential part of our culture.

🙌 The best team Berlin has to offer – or maybe even beyond. Don’t believe it? Apply now and see for yourself!

While we may still be considered pioneers today, with you on board we’re ready to take the market by storm – starting in the DACH region, and soon all across Europe.

You’ll join a motivated, open-minded, and dynamic team passionate about driving the energy transition forward. We believe this mission can only succeed together.

We’re excited to hear from you – Hoa will be in touch soon!