Principal Software Engineer (m/f/d)

<h2>1KOMMA5°</h2> <p>At <strong>1KOMMA5°</strong>, we pursue a clear vision: <strong>Living on wind and sunlight forever for free</strong>. To make this a reality, we are building the energy system of the future with Heartbeat AI. Want to be part of it?<br>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. </p> <p><strong>Want to take responsibility and build solutions that truly matter? Apply now and help us shape the energy world of tomorrow.</strong> </p> <p>Learn about our Product & Tech team!</p> <h2>Your mission</h2> <ul> <li>Shape the organisation's technical strategy and innovation efforts</li> <li>Accountable for consistent execution of technical decisions by setting clear direction and holding teams accountable for implementation</li> <li>Ensure continuously that our software architecture is shaped in close alignment with product management to support current and future product direction</li> <li>Lead architectural direction to enable the delivery of scalable, maintainable, and state-of-the-art solutions</li> <li>Translate business requirements into technical solutions</li> <li>Tackle and resolve deep technical challenges with urgency and precision</li> <li>Mentor and challenge engineers to accelerate their professional growth</li> <li>Build and scale a high-performance tech organisation and engineering culture</li> <li>Embed security and reliability as direct customer value</li> <li>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</li> <li>Drive the org's transformation to agentic engineering, reshaping how teams work so agents execute safely while humans stay accountable</li> </ul> <h2>Technologies you will work with include:</h2> <ul> <li>AI-assisted development with Cursor and agentic coding workflows</li> <li>Cloud & Infra: Google Cloud Platform, GKE (Kubernetes), Cloud Run, Terraform/IaC, Vercel</li> <li>Messaging & IoT: Eclipse Hono, MQTT, Mender</li> <li>Data & BI: PostgreSQL, BigQuery, SQLMesh, Looker</li> <li>Observability: Datadog, OpenTelemetry</li> <li>Languages: TypeScript (Nest.js), Java, Go, Flutter, Ruby on Rails</li> <li>DevOps: CI/CD pipelines (GitHub Actions)</li> <li>Linear, Notion, Figma, Miro</li> </ul> <h2>Your profile</h2> <ul> <li>Extensive hands-on experience in software development with multiple general-purpose programming languages for a minimum of 5 years</li> <li>A proven track record of architecting scalable and secure systems, demonstrating a strong commitment to quality</li> <li>Extensive experience in designing and implementing APIs that enable seamless integration and system communication</li> <li>An agile and result-oriented mindset, with a strong emphasis on collaboration and teamwork</li> <li>Experience communicating with stakeholders in business terms and understanding the technical implications of their requirements</li> <li>Industry-leading experience driving c