Full-Stack Product Engineer
Posted 5 Jun 2026
Advertised as “Full-Stack Product Engineer, Ruby on Rails (m/f/d) at Solar Startup”
BranchFactor Summary
The original posting with the fluff stripped out
- Expected experience
- 2+ yrs
- Management level
- Individual contributor
- Employment
- On-Site
- Contract
- Full-time
No salary listed for this role.
About Us
At VREY, we're building the EnergyOS for multi-family buildings.
Germany has over 3.3 million apartment buildings — and they are the blind spot of the energy transition. <1% solar penetration. <2% smart metering. Almost no flexibility or intelligent energy management.
At the same time, regulation is forcing property owners into major investment: solar is becoming mandatory, smart meters must be rolled out nationwide within five years, heating and mobility are electrifying. The apartment building is transforming from passive real estate into an active part of the decentralised energy infrastructure.
What's missing is an integrated system that makes this transition economically viable and operationally manageable.
VREY combines certified meter operation with proprietary software, enabling property owners to sell self-generated solar power directly to their tenants — simply, and without having to become an energy supplier themselves (§42b EnWG). Regulatory obligation becomes a profitable, predictable opportunity:
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Double-digit returns and asset appreciation for owners,
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~20% electricity cost savings for tenants, and
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digital infrastructure for storage, heat pumps, and flexibility.
We already manage a three-digit number of projects — including some of Germany's largest property holders and housing cooperatives — in all 16 federal states. In the course of our seed financing, we raised €3.3M from leading impact and energy VCs (including Rubio Impact Ventures, HTGF, and Kopa Ventures). We're now entering the next growth phase and expanding our team.
We're at the beginning of a structural market shift. Join us and help build the leading EnergyOS.
Your Profile
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You have 2+ years of professional experience building full-stack web applications, ideally with Ruby on Rails. Experience in comparable MVC frameworks (Django, Laravel, Spring Boot, NestJS) will also be considered, if you are truly motivated to learn and work with Rails.
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You have strong frontend development skills with solid fundamentals (HTML, CSS and JavaScript), as well as familiarity with the Rails-specific frontend technology (Hotwire, Turbo and Stimulus) and a framework like React or Vue.
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You have an you know interface patterns, think from a user's point of view and have worked with design systems.