Principal Engineer (m/f/d) - Remote in DE/UK/PT

🌍 About us - Join our mission to fight climate change We are looking for a Principal Engineer who can own our codebase quality and partner with our Head of Engineering in ensuring a purpose-fit architecture across our platform. In this unique role, you’ll be the most senior IC on our engineering team, partnering with our Head of Engineering to drive the most impactful technical initiatives of 2026, and raise our bar from “works most of the time” to finance-grade reliability. Cozero's platform turns enterprise activity data into auditable CO2 numbers - and the technical complexity is growing faster than the team. If you're excited about building an economy where every company creates an impact for a sustainable world and empowering companies to decarbonize and boost their business performance, we’d love to hear from you! We are open to hiring fully remotely for this role but require you to be located in one of the following countries: Germany, United Kingdom or Portugal. 🎯 What you’ll do: Own the technical architecture of a data platform (NestJS, Aurora PostgreSQL, SQS, Lambda, Cube.js/Snowflake) and drive its evolution toward reliability and scale. Lead cross-cutting technical initiatives from design through production release, observability, and long-term maintainability. Set engineering standards through tech doc reviews, architectural decisions, and reusable patterns that raise quality without slowing delivery. Act as the technical tiebreaker across the team - resolve cross-domain disagreements with clarity, data, and written proposals. Mentor engineers , distribute knowledge intentionally, and build the kind of engineering culture where a small team punches above its weight. ⭐ You'll thrive in this role if you: Bring 10+ years in Software engineering with 3+ years in a Staff/Principal IC role. Have led technical direction across a team of 5-15 engineers without being the manager - through RFCs, prototypes, and earning trust. Think in end-to-end systems - you can trace a data quality issue from a customer-facing report back through the analytics layer, processing pipeline, queue, and ingestion point. Have shipped a major system rewrite or migration incrementally - feature flags, phased rollouts - in a system where correctness matters as much as uptime. Are fluent in TypeScript/Node.js and comfortable with AWS (ECS, Lambda, SQS, Aurora). Are experienced with queue-based architectures (SQS FIFO, Kafka) at scale. Have a DevOps mindset - you own what you build, from technical design to deployment, monitoring, and operational health. Care about observability as a discipline - SLOs, dashboards, runbooks, post-mortems that become preventive guardrails Are great at written communication - clear tradeoff framing that other engineers actually read and reference. Nice to have: Familiarity with analytics layers (Cube.js, Snowflake, CDC pipelines) Climate tech, carbon accounting, or compliance-grade data systems Series A/B startup experience 💚 Why Join Cozero? Real impact - Your work directly reduces carbon emissions at scale. Not theoretical, actual tons of CO2. Right timing - Series A funded (€6.5M from Kvanted and ENV), growing fast, working with enterprise customers who trust us with their decarbonization journey. Exceptional team - Work directly with our founders Helen, Fabian, and Tiago. Multicultural, collaborative, and actually passionate about climate action—not just talking about it. You'll grow fast - Flat hierarchy. Your ideas ship. Direct impact on product and strategy. 📍 Where You'll Work Fully remote within Germany, Portugal or the UK. 🌱 Benefits 27 vacation days + 1 day life event leave (Wedding, Birth of child etc.) + national holidays (Depends on location) 500 EUR annual learning and development budget 500 EUR one-time home office setup 100 EUR monthly coworking budget (for those outside Berlin headquarters) VSOP (Virtual Stock Options) - share in Cozero's success Regular team events every year We're committed to building diverse teams and creating an inclusive workplace. We welcome applications from all qualified candidates regardless of ethnic origin, gender, religion or belief, age, or sexual identity. Our recruitment process is fair, objective, and based solely on the skills and qualifications required for this role.