Senior Fullstack Software Engineer Job at 1KOMMA5 (Hamburg)

Senior Fullstack Software Engineer

1KOMMA5

Location:
Germany , Hamburg ▼
Berlin
München

Category:
IT - Software Development

Contract Type:
Not provided

Salary:

Not provided

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Job Description:

At 1KOMMA5°, we pursue a clear vision: Living on wind and sunlight forever for free. To make this a reality, we are building the energy system of the future with Heartbeat AI. Want to be part of it?We bring together regional craftsmanship and scalable software: We don't think of solar, batteries, heat pumps, and e-mobility as isolated components, but control them as an intelligent, integrated overall system in our virtual power plant. Directly connected to the electricity market – in real time, fully automated. This way, energy is used when it is available from renewables and particularly cost-effective. By 2030, our goal is to transition 1.5 million households to renewable energies. Over 3,000 people are working towards this every day, at more than 80 locations worldwide, from Finland to Australia. Want to take responsibility and build solutions that truly matter? Apply now and help us shape the energy world of tomorrow. Become a part of our mission and learn more about our Product & Tech team! You will work on transforming the business of installing renewable technologies. With our core business software platform we streamline ground operations and rooftop installation to power the energy transition in private homes and small businesses world-wide. As a software engineer in 1KOMMA5°, you will be part of a cross-functional team alongside frontend and backend engineers, product managers and UX/UI developers. You will help build a self-organized tech team, responsible for developing, deploying and running their own solutions to contribute to those work streams.

Job Responsibility:

Develop and maintain the core Rails application with a focus on code health, modern patterns, and long-term stability
Lead technical implementation for complex projects within 6-week cycles, taking ownership from architectural design to shipping
Build pragmatic connections between the Rails monolith and satellite TypeScript/GCP services (Pub/Sub, Cloud Functions) without over-engineering
Proactively identify and resolve friction in tooling, CI/CD, and local environments to ensure the codebase remains enjoyable to work in
Drive high-quality async collaboration through clear documentation, architectural decision records (ADRs or RFCs), and comprehensive code reviews

Requirements:

proven experience in writing maintainable, self-describing, reusable and testable code with Rails and other major back-end or full-stack technologies in several past projects
experience designing and maintaining RESTful APIs
experience with measuring and improving performance
an agile and result-oriented mindset and a passion to support your team colleagues
interest or experience in human-centered software development
excellent knowledge of spoken and written English
residency in Germany

Nice to have:

German is a plus

What we offer:

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

Additional Information:

Job Posted:
March 01, 2026

Employment Type:

Fulltime

Work Type:

Remote work

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