A frontend developer is responsible for building the visual and interactive parts of a web application or website. Their job is to ensure users have a fluid and attractive experience when navigating a platform. To achieve this, they use technologies such as HTML, CSS, and JavaScript, along with frameworks like React, Angular, or Vue.js. Additionally, they focus on responsive design, accessibility, and performance optimization. A good frontend developer must collaborate with UX/UI designers and backend developers to ensure the application works correctly across all devices and browsers.