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

🌍 About us - Join our mission to fight climate change We’re building the carbon accounting platform that enterprises use for compliance reporting and decarbonization strategy. Our platform processes millions of data points to calculate auditable CO2 emissions and we need technical leaders who can own entire product domains. We are looking for a Lead Engineer to take end-to-end ownership of a core product domain in our carbon accounting platform. You’ll be the technical authority for their area: making architecture calls, shipping features in tight cycles, and being the one who keeps their domain reliable. This is a hands-on role - you write code daily, lead by shipping, and own your systems from design to production. If you want to own a core part of a climate tech platform and see your work directly impact how companies measure and reduce emissions, keep reading. 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 a product domain end-to-end - architecture decisions, feature delivery, reliability, and operational health for your area of the platform. Ship features in 2-3 day cycles - break down projects into small deliverables, write tech docs, and drive them to production. Design and build data validation and processing capabilities - ensuring customers can trust the numbers they see Lead technical discovery for your projects - implementation approach, testing strategy, rollout plan, risks - reviewed by peers before development starts Own what you build through production - deployment, monitoring, and incident response. ⭐ You'll thrive in this role if you: Bring 8+ years of experience in software engineering with 2+ years owning a product domain end-to-end . Have experience with data-intensive backend systems in B2B SaaS. Are a strong backend engineer fluent in TypeScript/Node.js - experienced with NestJS or similar frameworks, solid with PostgreSQL, comfortable navigating a React frontend when needed. Have owned a product domain before - not just implemented features, but made the architectural calls and been the person who knew how the whole thing worked. Care deeply about data correctness - you've built systems where wrong output is worse than no output, and you think naturally about validation and edge cases. Ship small and often - you're uncomfortable when PRs sit for days and you treat "in production" as the only definition of done. Have a DevOps mindset - you own your components from technical design to release, monitoring, and maintainability. Debug across layers - when something's wrong, you trace it end-to-end rather than pointing at someone else's service. Write clear technical documents that other engineers actually use. Familiarity with AWS (ECS, Lambda, SQS, Aurora). Nice to have Experience with data ingestion pipelines, ETL systems, or analytics tooling (Cube.js, Snowflake). Experience stabilizing or rewriting legacy systems incrementally. Climate tech, sustainability, or compliance-grade data systems. Series A/B startup experience. 💚 Why Join Cozero? Real impact - Your domain directly enables enterprises to measure and reduce their carbon footprint. 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.