A frontend developer crafts the user interface of a website or application, translating the design into code. They use languages like HTML, CSS, and JavaScript to create visually appealing, responsive, and user-friendly websites. They ensure the site's design is optimized for various devices and browsers and is accessible for all users. They also implement interactive features, like buttons, forms, or media. They collaborate with backend developers to connect the website to server-side functions and with designers to realize their vision. They also perform tests, fix bugs, and maintain the website's frontend code.