Senior Full-Stack Software Engineer (m/f/d)

We are looking for you to join our tech team in Berlin, Munich, or Hamburg. 1KOMMA5° is creating Germany's largest one-stop-shop for the sale, installation, and servicing of solar panels, heat pumps, electricity solutions, and charging infrastructure. And the best part? They are all interconnected!Become a part of our mission and learn more about our Product & Tech team!You will help transform the business of selling renewable technologies at scale. With our core marketing automation and CRM platforms. We redefine growth processes to accelerate the global energy transition empowering private homes and small businesses to adopt sustainable energy solutions.As a Senior Software Engineer at 1KOMMA5°, you will take technical ownership of key systems and features, driving architectural decisions and ensuring scalability, reliability, and performance. You’ll collaborate closely with other engineers, product managers, and stakeholders to shape our technical direction and deliver high-impact solutions. Beyond writing great code, you’ll mentor teammates, champion engineering excellence, and help evolve our development and deployment practices to the next level.Our Stack:

• Next.js/TypeScript for frontend applications & NestJS/TypeScript for backend applications
• TypeScript for CRM customizations & workflow automation with Windmill
• Ruby on Rails for one API-only application
• Infrastructure as code, deployment to Google Cloud, observability with Datadog
• Google Cloud Tasks and Delayed Job for background jobs

Key responsibilities include but are not limited to:

• Contribute as a senior full-stack engineer within a team of self-driven software developers
• Design, build, and maintain business-critical systems across the stack. From scalable backend services to performant, user-friendly frontends
• Translate complex and loosely defined business problems into clear, actionable technical solutions
• Champion clean architecture, component reusability, and maintainable UI patterns using modern frameworks (e.g. React, Next.js, or similar)
• Drive experiment-driven innovation and uphold strong engineering practices in testing, CI/CD, observability, and code quality
• Continuously improve developer experience by reducing technical debt, automating workflows, and documenting key decisions and operational processes
• Operate effectively in an asynchronous, outcome-oriented environment, managing your work autonomously and maintaining clear communication through documentation and structured updates
• Contribute to lightweight project management by defining milestones, ensuring technical feasibility, and aligning engineering work with product goals

You have:

• Extensive experience writing maintainable, reusable, and testable code in TypeScript, with strong skills in both frontend frameworks (e.g. React, Next.js) and backend technologies (e.g. Node.js, NestJS, or similar)
• Strong understanding of API design, data modeling, and system integration (RESTful or GraphQL)
• Proven ability to own features end-to-end, from UX and architecture to deployment and monitoring
• A pragmatic, product-focused mindset that balances technical excellence with delivering customer value
• Curiosity and initiative to explore new tools and methods that improve product quality and engineering efficiency
• Excellent written and spoken English; German is a plus
• Residency in Germany

• You are part of an international, dynamic, and highly motivated team of people who have proven to make things happen
• With your work, you accelerate the "energy transition" and hence have a direct impact on our climate
• Work with and learn from other super-smart colleagues
• You will enjoy direct contact with core decision-makers
• You will enjoy the best chances of entering full-time in one of Europe’s most thriving scaleups
• You work remotely (Germany-wide), with offices in Hamburg, Berlin or Munich
• Create a healthy balance alongside your work and enjoy all the benefits of the EGYM Wellpass
• Benefits and discounts are yours with Futurebens
• Whether city bike or e-bike - be flexible with our job bike leasing and do something good for the environment at the same time