Senior Fullstack Engineer

Sweep is hiring a Senior Fullstack Engineer to work on our sustainability data intelligence platform. Climate change is the defining issue of our time. By empowering companies with technology that helps them manage their climate impact, we believe Sweep can make a meaningful contribution to a better future for all of us. Ok, sounds promising. What will I be doing? As a key player in our Engineering team, you'll own features end-to-end from data models and backend systems to the interfaces that make sustainability data actionable for our users. Your work will sit at the heart of a platform used by major enterprises to track greenhouse gas emissions, meet regulatory requirements, and drive real decarbonization. More specifically, your mission will involve: 1. Build and own features of the core product 🌱 Design and implement end-to-end features, from database schema and backend logic to GraphQL API and frontend UI Take full ownership of significant parts of the system, including reliability, performance, and long-term maintainability Contribute to and challenge our technical architecture as we scale Participate in every stage of the development lifecycle from design to rollout and smooth operation in production 2. Bring genuine backend depth ⚙️ Design robust data models and schemas that perform at scale Build and operate backend services, including background jobs, async pipelines, and integrations with third-party systems Own observability: instrument systems, define meaningful metrics, and respond to incidents with confidence Identify and address security risks proactively from API design to infrastructure exposure Automate deployments via our CI/CD systems and improve development processes 3. Be a team force multiplier 👫 Lead technical design on significant features and share your experience openly Review pull requests with rigour and care raising the bar for the whole team Participate actively in team rituals (standups, planning, retros) Contribute to our culture of quality: incremental, well-tested, observable changes 4. Pursue quality 🔍 Be a quality gatekeeper champion clean code, good test coverage, and solid engineering practices Improve processes and methodologies to reach the highest standards Bring excellence in your own work and help others do the same That's just right for me. What do I need to bring? Good you asked. Some more details on who we’re looking for Qualifications 🏆 5+ years of experience in backend development, with a track record of shipping at scale Deep command of backend fundamentals: relational databases, distributed systems, API design, observability, and security Comfortable with the full stack able to build and iterate on frontend features (React/TypeScript) without being blocked Demonstrated ability to work in complex systems and make sound architectural decisions Ability to deliver across competing priorities with autonomy and clear communication Strong plus: experience with Ruby on Rails, especially in a high-scale production environment Qualities 🧠 You have a genuine passion for solving complex technical problems and you bring the depth to do it well You take ownership: of your code, your features, and your impact on the team You value clean, well-tested software and understand that quality is a long-term investment You communicate clearly, collaborate naturally, and raise the people around you You're enthusiastic and self-motivated you don't wait to be told what to do next You care about our mission of building a more sustainable future Great, and what's in it for me? You'll be joining a company with a clear mission, real traction, and a team that cares deeply about doing things right. We're big believers in creating successful businesses that are good for everyone, including society and the planet. That's why we have a B Corporation status. Our hybrid work model, with offices in Paris, London, Montpellier, and Denver, gives you the flexibility to balance your personal and professional l...