Worked on improving the API documentation for the vitest-dev/vitest repository, focusing on enhancing clarity and accuracy for end users. Addressed a specific issue by correcting a typo in the documentation for the toHaveBeenCalledExactlyOnceWith method, ensuring that developers referencing the API receive accurate information. Employed technical writing and documentation skills, utilizing Markdown to maintain consistency with existing documentation standards. The work involved careful editing and collaboration with the documentation team, leveraging version control practices through commits and pull requests. This contribution aimed to reduce onboarding time, minimize support queries, and support the maintainability of the project’s documentation resources.