A MonoDevelop developer primarily focuses on building cross-platform applications using MonoDevelop, an open-source integrated development environment (IDE). The developer writes, debugs, and tests code, primarily in C# language, while ensuring the applications are compatible with different operating systems like Linux, Windows, and macOS. They also manage the application lifecycle, maintain the codebase, and fix bugs. They collaborate with other team members to design user-friendly and efficient software solutions. Additionally, they utilize MonoDevelop's features like advanced text editing, project management, and integrated debugging to optimize application performance.