A CloudFoundry developer designs, develops, and deploys applications on the CloudFoundry platform, a cloud-based, open-source platform as a service (PaaS). They manage the full lifecycle of applications, from initial development to updates. They write code, troubleshoot issues, and collaborate with other developers to ensure smooth, continuous delivery of applications. They use CloudFoundry's features for scaling, routing, service brokering, and managing application health. They also leverage its support for a variety of programming languages and frameworks, allowing them to create and deploy applications in the most suitable language for the task at hand.