The front-end is the part of an application users interact with directly: the interface displayed in the browser or on screen, as opposed to the back-end running on servers.
A front-end developer turns designers' mockups into a working interface. They rely on three building blocks: HTML for structure, CSS for styling, JavaScript (often TypeScript) for interactivity. Most projects use a framework or library such as React, Vue.js, Angular or Svelte.
The job goes well beyond integration work:
- managing application state and API calls
- loading and rendering performance
- accessibility and cross-browser compatibility
- adapting to every screen size (responsive)
The boundaries are shifting: with server-side rendering (Next.js, Server Components), part of front-end work now runs on the server.
Why it matters when hiring
The classic trap is confusing an HTML/CSS integrator with a front-end developer: the former reproduces mockups in HTML and CSS, the latter designs the architecture of a complex client-side application. In the interview, get candidates talking about state management, performance and testing rather than the list of frameworks they know. A feel for design and accessibility is a real plus.