GFL Environmental Inc. in Vaughan, Canada seeks a Senior Full-Stack Developer to lead the modernization of core enterprise apps. You will deconstruct legacy .NET 4.8 MVC monoliths and re-engineer them into .NET 6+/microservices with a React frontend hosted on AWS. The role is not maintenance; it focuses on re-engineering for scalability, cloud-native design, and robust RESTful APIs. You will drive CI/CD pipelines and collaborate with cross-functional teams to deliver high-performance solutions.