Stanislav Vasilev refactored the backend of Codetracer, focusing on improving code organization and maintainability without altering user-facing behavior. He modularized core backend logic by moving startCore into a dedicated backends file, aligning the codebase with internal style guidelines and addressing minor formatting issues. Working in Nim, Stanislav emphasized backend development and code refactoring, reducing technical debt and clarifying module boundaries to support future enhancements. His work in the metacraft-labs/codetracer repository laid a foundation for easier testing and incremental feature development, demonstrating a methodical approach to code quality and collaboration on internal standards within a short project timeframe.