Senior FullStack Developer .NET & React

Somos especialistas em **transformação tecnológica** , unindo expertise humana à IA para criar soluções tech escaláveis. Com mais de 8,000 CI\&Ters ao redor do mundo, já formamos parcerias com mais de 1,000 clientes durante nossos 30 anos de história. Inteligência Artificial é nossa realidade. **Importante** : se você reside na Região Metropolitana de Campinas, sua presença nos escritórios da cidade será obrigatória, conforme a política de frequencia vigente. **Description** **ABOUT THE ROLE** At 3Degrees, we are transitioning from legacy proprietary systems to an AI\-first, enterprise\-grade technology platform. We are looking for a Full Stack Engineer to lead the automation of our Receipts Management process, a mission\-critical initiative involving the migration of legacy data to ION’s Carbon Zero platform. You will be a founding member of an agile unit dedicated to decommissioning 17\-year\-old systems and replacing them with high\-performance, integrated solutions. In this role, you will collaborate with our US\-based teams to build "Callisto," our internal data management platform, ensuring straight\-through processing (STP) for environmental commodities. This is a high\-impact opportunity to apply modern engineering standards and AI\-assisted development to solve complex climate tech challenges at startup velocity. **WHAT YOU'LL DO** **Legacy Migration \& Integration:**  Lead the transition of core trading functions from Legacy application to the ION’s Carbon Zero platform, focusing on receipt processing automation across :40 global registries. **Full Stack Development:**  Build and maintain the Callisto UI using React and TypeScript, while developing robust back\-end business logic and APIs in C\#/.NET Core or Python. **Registry Automation:**  Develop and support integrations with external EAC (Environmental Attribute Certificates) tracking systems via APIs or AI\-enabled RPA functionality. **AI\-First Execution:**  Actively use AI\-assisted coding tools (e.g., Cursor, Claude Code, GitHub Copilot) to accelerate development speed and maintain high code quality. **Cross\-Functional Collaboration:**  Partner with US\-based technical leads and business stakeholders to map integration touchpoints across Salesforce, NetSuite, and our operational databases. **ABOUT YOU** You are a versatile builder who thrives in a fast\-paced, "AI\-First" engineering environment. You possess a strong balance of frontend craft and backend rigor, with a specific interest in environmental markets and decarbonization. You are comfortable navigating legacy architectures while architecting modern, scalable alternatives that leverage automated workflows. 8\+ years of experience in C\#/.NET/Python development and React/TypeScript frontend design. Advanced database skills (Azure SQL, Managed Instances) with the ability to analyze and optimize complex schemas. Professional\-level English proficiency (C1\+) with the ability to communicate complex technical decisions to US\-based stakeholders. A "product mindset" with the ability to move from prototype to production in 6–8 week cycles. Availability to maintain high overlap (at least 6 hours) with US Pacific Time (PT) working hours. Demonstrated experience using AI tools (LLMs, agentic frameworks) to accelerate your personal development workflow. **HOW WE DEFINE SUCCESS** **Within the first 30 days:** Gain a firm grasp of the "Callisto" architecture, the ION Carbon Zero roadmap, and the specific data structures within the legacy SQL trading environment. Build strong cross\-functional relationships with US\-based technical leads and understand the agile unit's communication and deployment cadences. Successfully clear 3\-5 initial feature/bug tickets to demonstrate proficiency in the tech stack and AI\-assisted development tools. **Within the first 90 days:** Hone development skills within the environment to contribute to the Receipts Management SOW in a meaningful way, delivering the first set of automated registry integrations. Establish a consistent high\-velocity coding loop using AI\-assisted tools (Cursor/Claude/Copilot), ensuring all contributions meet documented security and documentation standards. Actively participate in the Discovery process for North American registry integrations, helping to map technical debt and architectural requirements. **Within the first 6 months:** Contribute independently as a senior developer, co\-leading the technical execution of the North American registry integration phase. Help the team meet department goals by delivering production\-ready APIs and UI components that reduce manual processing time for the trading team. Demonstrate a firm grasp of the end\-to\-end SDLC by independently managing complex project slices from prototype to MVP. **Within 1 year:** Demonstrate success across all automation goals, achieving 90%\+ straight\-through processing for targeted registry transfers and retirements. Successfully decommission legacy components for the receipts process, migrating all core functionality to a stable, integrated enterprise platform. Serve as a mentor for the engineering team on AI\-first development best practices, driving continuous improvement in delivery speed and code reliability. **Nossos benefícios:** \- Plano de saúde e odontológico; \- Vale alimentação e refeição; \- Auxílio\-creche; \- Licença parental estendida; \- Parceria com academias e profissionais de saúde e bem\-estar via Wellhub (Gympass)  TotalPass; \- Participação nos Lucros e Resultados (PLR); \- Seguro de Vida; \- Plataforma de aprendizagem contínua (CI\&T University); \- Clube de descontos; \- Plataforma online gratuita dedicada à promoção da saúde física, mental e bem\-estar; \- Curso gestante e parentalidade responsável; \- Parceria com plataformas de cursos online; \- Plataforma para aprendizagem de idiomas; \- E muitos outros Mais detalhes sobre os nossos benefícios aqui: https://ciandt.com/br/pt\-br/carreiras Na CI\&T, a inclusão começa no primeiro contato. 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