Cozero's platform turns enterprise activity data into auditable CO2 numbers. Our platform is trusted by large enterprise customers with their full decarbonization journey.
We are at an inflection point. The codebase works. The customers are real. The complexity is growing faster than the team. 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.
You’ll be the most senior IC on our engineering team, partnering with our Head of Engineering to define and drive the most impactful technical initiatives of 2026, and raise our bar from “works most of the time” to finance-grade reliability.
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!
📍Fully remote - Germany, United Kingdom or Portugal.
🎯 What you’ll own:
Technical architecture of our data platform (NestJS, Aurora PostgreSQL, SQS, Lambda, Cube.js/Snowflake) and its evolution toward reliability and scale.
Cross-cutting technical initiatives from design through production: release, observability, and long-term maintainability.
Engineering standards through tech doc reviews, architectural decisions, and reusable patterns that raise quality without slowing delivery.
Technical decision-making across the team - resolving cross-domain disagreements with clarity, data, and written proposals.
Knowledge distribution, mentoring engineers and building habits that reduce single points of failure.
Have 8+ years in software engineering, with demonstrated experience leading technical direction across a team, whether in a formal Staff/Principal title or equivalent scope.
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).
Have a hands-on experience 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.
Communicate clearly in writing - 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 technical challenge - You're joining a growing system with real complexity. Work directly reduces carbon emissions at scale. Not theoretical, actual tons of CO2.
Actual climate impact - 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. And 9+ engineers across Germany, Portugal and the UK. Multicultural, senior-leaning, collaborative, and actually passionate about climate action.
You'll grow fast - Flat hierarchy. Your ideas ship. Direct impact on product and strategy.
Fully remote within Germany, Portugal or the UK.
🌱 Benefits
Competitive base salary
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.
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