Empresa: CI&T
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. At CI&T, we are looking for a skilled and motivated Senior .NET Backend Developer to join one of our delivery teams. You will design, build and evolve scalable, secure and maintainable backend services using a modern .NET stack, working closely with Product, Architecture, QA and Frontend colleagues in a collaborative, multicultural and fast-moving environment. Your responsibilities • Design, develop and maintain RESTful APIs and backend services using C# and .NET 8+. • Apply Clean Architecture, SOLID and KISS principles to keep code modular, reusable and simple. • Build event-driven and asynchronous integrations using messaging platforms such as Azure Service Bus, RabbitMQ or Kafka. • Model, query and optimize relational databases such as PostgreSQL and SQL Server, using Entity Framework Core. • Work with document databases such as MongoDB, when needed. • Implement secure authentication and authorization using OAuth2/OIDC and JWT. • Write and maintain automated unit and integration tests using tools such as xUnit, NSubstitute and Bogus. • Contribute to CI/CD pipelines, including Azure DevOps and YAML pipelines, and follow agreed branching strategies such as GitFlow. • Instrument services for observability, including structured logging, metrics and tracing, and help diagnose production issues. • Critically read, validate and review code, including code generated by AI tools, to uphold quality, security and performance standards. • Take part in code reviews, technical refinement and estimation, and help mentor less experienced developers. • Work with technical and non-technical stakeholders to turn requirements into pragmatic, maintainable solutions. Requirements for this challenge • Solid experience as a backend developer working with C# and .NET, ideally .NET 8+, including production-grade RESTful APIs. • Strong knowledge of object-oriented design, SOLID principles, design patterns and Clean Architecture. • Hands-on experience with MediatR, AutoMapper and Entity Framework Core. • Experience with relational databases such as PostgreSQL or SQL Server, including data modelling and query optimization. • Experience with distributed systems and messaging, using technologies such as Azure Service Bus, Rebus, RabbitMQ, Kafka or equivalent. • Practical use of AI tools in software development, such as GitHub Copilot, Claude, OpenAI APIs or similar, including AI-assisted code generation, testing and refactoring. • Experience building autonomous or semi-autonomous agents for software development, or knowledge of prompt engineering and evaluating AI output quality. • Experience with automated testing, including unit and integration testing and the use of test doubles. • Working knowledge of Docker and Docker Compose. • Familiarity with observability tools such as Datadog, Grafana, Application Insights or the ELK Stack. • Experience with Git, CI/CD pipelines and Azure DevOps, or similar tools. • Good communication skills and a collaborative, ownership-driven mindset. • Good spoken and written English (upper-intermediate or above). Nice to have • Knowledge of CQRS and Domain-Driven Design (DDD). • Experience with MongoDB, including document modelling and aggregation. • Knowledge of Infrastructure as Code, using technologies such as Terraform, Bicep or ARM. • Exposure to a frontend framework such as React, Angular or Vue, including API integration from the client side. • Experience working in polyglot environments, such as Node.js, Python or Java. #midsenior #Li-MG04 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.