Project Y is hiring on behalf of a one of Germany’s fastest-growing PropTech startups.

Based in Berlin and with an international team, the venture (Heidi Systems) is transforming the way energy consumption data is collected and managed.

We’re looking for a Senior Full-Stack Engineer to join an experienced, fast-moving team and take ownership of building, maintaining, and scaling a product used by customers across Europe.

As a Senior Full-Stack Developer, you will take ownership of building our new web dashboard - a responsive, high-performance interface for property managers and tenants to view, manage, and analyze real-time consumption data. You’ll work closely with product and backend teams to design scalable features, implement secure integrations, and ship elegant UI components.

This is a high-agency role suited to someone who thrives in autonomous environments, enjoys solving complex technical problems, and can translate product goals into elegant, scalable code. You’ll be trusted to ship independently, contribute to product direction, and ensure every release is robust and production-ready.

About the company Their intelligent system enables wireless and automatic reading of heat and water meters — giving property managers and residents real-time transparency, regulatory compliance, and full digital control over energy data.

With operations across Germany, Austria, Denmark, and Switzerland, Heidi Systems combines innovation, sustainability, and reliability to make buildings smarter and more efficient. Why join: ✅ Work at the intersection of IoT, sustainability, and digitalization ✅ Be part of a scaling European tech company with a strong mission ✅ Contribute to climate-friendly energy management in real estate

Your Responsibilities

• Build and maintain a high-performance web dashboard using Next.js, Supabase, TailwindCSS, Drizzle ORM, and TanStack Query Implement secure user authentication and authorization with Supabase Auth
• Integrate RESTful APIs and ensure efficient, scalable data flows Write clean, maintainable, and well-documented code using TypeScript

Must-Haves:

• 5 + years of professional full-stack development experience.
• Strong expertise in Next.js, React, TypeScript, and TailwindCSS
• Proven experience with Supabase (Auth, Database, and Storage) and Drizzle ORM
• Familiarity with TanStack Query, RESTful APIs, and performance optimization techniques
• Experience building and deploying scalable, production-grade web applications
• Strong sense of UI/UX detail and modern design aesthetics

Nice-to-Haves

• Experience building SaaS or B2B products, especially in proptech. UI/UX sensibility and ability to implement pixel-perfect interfaces.
• Interest in contributing to product direction or suggesting new technical approaches.
• Familiarity with edge functions, cloud infrastructure, and performance monitoring tools.