[Job-32156] Senior .NET Backend Developer

Job description

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