[Job-32277] Senior FullStack Developer (.NET/Javascript/React)

At CI&T, we help large enterprises transform the potential of AI into real business impact with AI Deployment, AI-native execution, and tech-integrated business solutions. With 30 years of experience in technological transformation, we accelerate innovation with expertise in Agentic SDLC, Application modernization, Data & AI, Martech and Business strategy. We are 8,000 CI&Ters across more than 25 countries, collaborating to build solutions with real impact. AI is already part of how we work, evolve, and innovate every day. Job Overview: We are on the lookout for a passionate and experienced Senior Fullstack Developer to join our engineering team. The ideal candidate will have a strong background in web application development—specifically with .NET Core—and the flexibility and eagerness to adapt to and learn new technologies, including legacy ASP.NET and modern JavaScript frameworks. Additionally, a solid understanding of frontend engineering using React is essential to build, maintain, and evolve high-performance user interfaces. Key Responsibilities: - Feature Engineering & Delivery: Design, build, test, and maintain scalable, secure, and resilient fullstack applications using .NET Core and React. - Security & Best Practices: Actively address security vulnerabilities across both frontend and backend codebases, adhering to modern secure coding standards and OWASP principles. - Architecture Implementation: Translate architectural guidelines into clean, maintainable, and well-tested code, contributing actionable technical insights to team design discussions. - Performance Optimization: Continuously monitor, troubleshoot, and optimize application performance, reliability, and backend/frontend interactions. - AI Tooling & Developer Velocity: Utilize AI tools and agentic workflows (e.g., Claude Code) to accelerate feature delivery, cross-file refactoring, and automated testing. - Quality & Testing Ownership: Drive test coverage (unit, integration, end-to-end) and enforce robust code quality and CI/CD standards within the development pipeline. - Team Leadership & Mentorship: Conduct thorough peer code reviews, mentor junior and mid-level developers, and foster a collaborative, continuous-learning culture. Technical Skills: - Claude Code Environment Experience: Proficient in using Claude Code via terminal, IDE, and GitHub integrations to accelerate codebase onboarding, cross-file refactoring, and feature delivery. - Agentic SDLC Experience: Practical experience applying AI agents and AI-driven workflows across the software development life cycle. - Backend Mastery: Proven experience in backend development with deep expertise in .NET Core (C#) and familiarity with ASP.NET. - Frontend Engineering: Strong hands-on proficiency in JavaScript, TypeScript, and modern frontend frameworks like React. - Software Design: Solid understanding of core software development principles (SOLID, DRY) and microservices/monolithic design patterns. - Data Management: Experience with relational and non-relational databases (e.g., SQL Server, PostgreSQL, MySQL) including query optimization and schema design. - Cloud & DevOps: Familiarity with cloud computing platforms (especially AWS), containerization, RESTful API design, Git, and automated CI/CD pipelines. Soft Skills: Proactive Ownership: Demonstrates initiative by identifying challenges early, proposing pragmatic solutions, and taking end-to-end responsibility with minimal supervision. - Critical Thinking: Questions underlying assumptions and analyzes problems from foundational concepts up, ensuring deep technical comprehension before taking action. - Adaptability & Continuous Learning: Eagerness to learn new languages, frameworks, and engineering tools as technical demands evolve. - Problem Solving: Strong analytical skills with a track record of diagnosing and resolving complex technical issues in production environments. - Communication & Collaboration: Excellent written and verbal communication skills, with a team-oriented mindset and ability to bridge discussions between product and engineering. - AI Enthusiasm: A genuine interest in leveraging AI technologies to enhance development efficiency and code quality.