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 hiring a Mid-Level .NET Developer to maintain and improve our web applications built with .NET and React. A key focus of this role is modernizing how the applications handle user login and security (authentication and authorization), and updating our code to use newer .NET Core versions.
You will work with a team that values clear communication and collaboration. You will talk directly with stakeholders to understand what needs to be done and help prioritize tasks.
What You Will Do
- Maintain and improve existing ASP.NET and .NET Core web applications
- Design and build modern login and security systems (OAuth2, OIDC, JWT, and identity providers)
- Plan and execute upgrades to newer .NET Core versions
- Work with AWS, MySQL, PostgreSQL, and external services
- Use Bitbucket and automated testing tools (Playwright) to deliver quality code
- Work with CI/CD pipelines to automate testing and deployment
- Communicate in English with stakeholders to discuss priorities and understand requirements
What You Need to Know
- 5+ years of professional experience with .NET (C#) and web development
- Proven experience with authentication and authorization systems
- Proven experience with upgrading .NET versions
- Experience with React in production applications
- Experience with AWS and relational databases (MySQL, PostgreSQL)
- Experience with third-party API integrations
- Comfortable with Bitbucket/Git and version control
- Experience with automated testing (Playwright is a plus)
- Advanced English proficiency and strong communication skills
#LI-THAI23
Skills Required
- 5+ years of professional experience with .NET, C#, and web development
- Experience with authentication and authorization systems
- Experience upgrading .NET versions
- Production experience with React
- Experience with AWS
- Experience with relational databases, including MySQL and PostgreSQL
- Experience with third-party API integrations
- Experience with Bitbucket, Git, and version control
- Experience with automated testing
- Experience with Playwright
- Advanced English proficiency
- Strong communication skills
What We Do
CI&T is your end-to-end digital transformation partner. As a digital native, we bring a 27-year track record of accelerating business impact through complete and scalable digital solutions. With a global presence of 6,000+ professionals in strategy, research, data science, design and engineering, we unlock top-line growth, improve customer experience and drive operational efficiency.
