Senior Fullstack Engineer - React/JS Remote position, only for professionals based in Argentina or Uruguay RYZ Labs is seeking a Full Stack Engineer (React / JavaScript) to join one of our clients’ teams building intelligent, secure, and scalable digital experiences. In this role, you will contribute to modernizing existing applications while building new user-facing features using React and modern JavaScript technologies. You will work closely with cross-functional teams including backend, product, and platform engineers to deliver reliable and scalable solutions. The ideal candidate will help evolve the front-end architecture while navigating a legacy environment and integrating modern technologies. Responsibilities Develop and maintain modern React-based user interfaces using clean, reusable, and maintainable code. Build responsive and intuitive UI components using React and Material UI (MUI). Implement styling using SCSS while maintaining consistent design and UI standards. Integrate front-end applications with REST APIs and backend services. Collaborate with backend engineers to deliver end-to-end product functionality. Participate in the modernization of legacy applications and help migrate existing features to modern front-end frameworks. Maintain and improve existing codebases while ensuring scalability, performance, and maintainability. Write and maintain unit and integration tests to ensure code quality. Review code and provide constructive technical feedback to team members. Debug and resolve production issues across the application stack. Contribute to front-end architecture decisions and development best practices. Participate actively in Agile ceremonies, including stand-ups, sprint planning, and retrospectives. Create and maintain technical documentation. Stay current with modern front-end development practices and tooling. Qualifications 5+ years of professional experience in software development. Strong experience with React and modern JavaScript frameworks. Proficiency in JavaScript and/or TypeScript. Experience building UI using Material UI (MUI). Strong experience with SCSS or modern CSS frameworks. Experience integrating REST APIs into modern web applications. Proficiency with Git version control. Experience building responsive and user-friendly web applications. Experience working in Agile development environments. Strong collaboration and communication skills across engineering teams. Nice to Have Familiarity with ASP.NET WebForms and Razor templating. Ability to read and understand C# code. Experience with Gulp or similar asset pipeline tools. Experience with testing frameworks such as NUnit or Jest. Familiarity with Azure DevOps and NuGet. Experience working in legacy modernization projects. \n\n