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. We are looking for a Senior .NET Engineer/Tech Lead ou Architect to join our team and contribute to the development and integration of complex software solutions focused on back-end development. This role will require working closely with a multicultural team spread across Brazil, Colombia, the UK, and the USA, with all communication conducted in English. Key Responsibilities: Design, build, and maintain back-end services using C#, ADO.NET, and SQL Server. Implement and evolve SOAP and REST APIs, ensuring best practices and versioning standards. Ensure service reliability through unit and integration testing, troubleshooting, and root-cause analysis. Collaborate on integration between various systems and services, applying software design patterns. Conduct code reviews and provide mentorship to junior team members. Stay up to date with emerging technologies and industry trends, applying them to improve existing solutions. Contribute to CI/CD workflows and best practices to enhance development efficiency. Required Skills and Qualifications: Strong experience with .NET Framework and .NET Core in production systems. Solid understanding of ADO.NET and SQL Server, with experience in database design and performance tuning. Hands-on experience with SOAP and RESTful services. Proficiency in XML serialization/deserialization. Strong understanding of software design patterns and best practices. Effective communication skills and resilience in fast-paced, multicultural teams. Advanced/fluent English proficiency. Soft Skills: Proactive ownership of tasks with a mindset for continuous improvement. Strong communication skills across technical and non-technical audiences. Collaborative team player who values shared success. Ability to adapt to ambiguity and shifting requirements. Nice-to-Have Skills: Experience with cloud platforms, preferably Azure. Familiarity with specification-driven development and agentic approaches to software development. Exposure to Agile development methodologies. If you are a seasoned back-end developer looking to take on complex challenges in a dynamic environment, we invite you to apply and become a part of our diverse team! #LI-JM2 Our benefits:   -Health and dental insurance -Meal and food allowance -Childcare assistance -Extended paternity leave -Partnership with gyms and health and wellness professionals via Wellhub (Gympass) TotalPass; -Profit Sharing and Results Participation (PLR); -Life insurance -Continuous learning platform (CI&T University); -Discount club -Free online platform dedicated to physical, mental, and overall well-being -Pregnancy and responsible parenting course -Partnerships with online learning platforms -Language learning platform And many more!   More details about our benefits here: https://ciandt.com/br/pt-br/carreiras   At CI&T, inclusion starts at the first contact. If you are a person with a disability, it is important to present your assessment during the selection process. See which data needs to be included in the report by clicking here.This way, we can ensure the support and accommodations that you deserve. If you do not yet have the assessment, don't worry: we can support you in obtaining it.   We have a dedicated Health and Well-being team, inclusion specialists, and affinity groups who will be with you at every stage. Count on us to make this journey side by side.