Principal Software Engineer (m/f/d)

Title: Principal Software Engineer (m/f/d) Location: Berlin, Germany ## 1KOMMA5° 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.** Learn about our Product & Tech team! ## Your mission * Shape the organisation's technical strategy and innovation efforts * Accountable for consistent execution of technical decisions by setting clear direction and holding teams accountable for implementation * Ensure continuously that our software architecture is shaped in close alignment with product management to support current and future product direction * Lead architectural direction to enable the delivery of scalable, maintainable, and state-of-the-art solutions * Translate business requirements into technical solutions * Tackle and resolve deep technical challenges with urgency and precision * Mentor and challenge engineers to accelerate their professional growth * Build and scale a high-performance tech organisation and engineering culture * Embed security and reliability as direct customer value * Architect our systems and APIs so AI agents operate as first-class users with machine-readable contracts and structured errors that let agents self-correct * Drive the org's transformation to agentic engineering, reshaping how teams work so agents execute safely while humans stay accountable ## Technologies you will work with include: * AI-assisted development with Cursor and agentic coding workflows * Cloud & Infra: Google Cloud Platform, GKE (Kubernetes), Cloud Run, Terraform/IaC, Vercel * Messaging & IoT: Eclipse Hono, MQTT, Mender * Data & BI: PostgreSQL, BigQuery, SQLMesh, Looker * Observability: Datadog, OpenTelemetry * Languages: TypeScript (Nest.js), Java, Go, Flutter, Ruby on Rails * DevOps: CI/CD pipelines (GitHub Actions) * Linear, Notion, Figma, Miro ## Your profile * Extensive hands-on experience in software development with multiple general-purpose programming languages for a minimum of 5 years * A proven track record of architecting scalable and secure systems, demonstrating a strong commitment to quality * Extensive experience in designing and implementing APIs that enable seamless integration and system communication * An agile and result-oriented mindset, with a strong emphasis on collaboration and teamwork * Experience communicating with stakeholders in business terms and understanding the technical implications of their requirements * Industry-leading experience driving cross-functional teams and enforcing engineering alignment in fast-paced environments, including making and following through on critical technical decisions * Experience designing systems and APIs for agent consumption, with structured errors and clear contracts that let agents self-correct * Capability to guide an engineering team through the shift to agentic engineering, reshaping workflows so agents execute safely while humans stay accountable for every outcome * Strong verbal and written communication skills in English, with proficiency in German considered a plus ## Benefits * 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 * Individualised opportunities for professional development * Reporting directly to the CTO