🌍 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, helping companies understand and reduce their climate impact.

We are looking for a Senior Software Engineer who will play a key role in shaping and building a core product domain within our carbon accounting platform, working on complex backend systems that ingest, validate, and process large volumes of data.

This is a highly hands-on role where you will collaborate closely with other engineers on architecture decisions, design reliable systems and deliver features in fast iterations.

You’ll work across the full lifecycle of your systems: from design and implementation to deployment and monitoring in a team that values pragmatism, ownership, and shipping impact to production.

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:

• Contribute to the development of a core product domain: collaborating on architecture decisions, feature delivery, reliability, and operational health for your area of the platform.

• Design and build data validation and processing capabilities: helping ensure customers can trust the numbers they see.

• Ship features in fast iterations: break down projects into small deliverables, write technical documentation, and deliver them to production.

• Contribute to technical discovery for your projects: shaping implementation approaches, testing strategies, rollout plans, and identifying risks, in collaboration with peers.

• Take responsibility for what you build in production: supporting deployment, monitoring, and incident response.

🧰 Tech Stack

• TypeScript / Node. js

• NestJS

• PostgreSQL

• React

• AWS (ECS, Lambda, SQS, Aurora)

• Data pipelines / ETL

⭐ You'll thrive in this role if you:

• Bring 5+ years of experience in software engineering.

• 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 and comfortable navigating a React frontend when needed.

• Have worked on complex product domains - contributing to architectural decisions and understanding how different parts of the system interact.

• Care about data correctness - you've built systems where wrong output is worse than no output, and you think naturally about validation, idempotency, 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 take responsibility for the components you build, 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 documentation that other engineers actually use.

• Familiarity with AWS (ECS, Lambda, SQS, Aurora).

Nice to have:

• Experience with data ingestion pipelines, or analytics tooling (Cube.js, Snowflake)

• Exposure to climate tech, sustainability, or compliance-grade data systems

• Experience improving or incrementally modernizing legacy systems

• Startup experience (Series A/B stage)
  

💚 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.