Which professional is responsible for writing the HTML and CSS code for a website?

The role that is primarily responsible for writing the HTML and CSS code for a website is that of a web developer. Web developers have a deep understanding of programming and markup languages, which includes not only HTML and CSS but often JavaScript as well. They focus on building the technical aspects of a website, ensuring that the design and functionality work seamlessly together.

While a web designer may create the aesthetic and experiential aspects of a site, such as layout and color schemes, they typically focus more on the visual and conceptual side rather than the actual coding. A UX designer prioritizes the user experience, which involves research, prototyping, and user testing to improve how users interact with a website, but does not usually involve writing code. A system administrator is responsible for maintaining and managing computer systems and networks rather than web development.