Frontend

The frontend is the layer of a web application that is rendered and executed in the user's browser. It covers everything the visitor perceives and interacts with: content structure, visual design, animations and responses to clicks and input. Unlike the backend, which runs on a server and stays out of sight, the frontend runs on the end user's device.

How the frontend works

Three technologies form the foundation of the frontend, all interpreted natively by browsers:

• HTML — defines the structure and semantics of content, such as headings, paragraphs, lists and forms;
• CSS — controls presentation: colours, typography, grids and responsiveness across screen sizes;
• JavaScript — adds logic and interactivity: event handling, fetching data from APIs and updating the page without a full reload.

In modern projects this layer is organised with frameworks and libraries such as React, Vue or Angular, which let developers build interfaces from reusable components and manage application state cleanly. Before deployment, the code passes through a build step — bundling and minification handled by tools like Vite or Webpack.

Practical application

Frontend developers build the interfaces of online stores, admin panels, SaaS dashboards and marketing sites. Their daily work balances clean layout, digital accessibility (WCAG), performance measured by Core Web Vitals, and correct behaviour across mobile devices and different browsers.

A finished frontend is typically a set of static files — HTML, CSS, JavaScript and images — that can be served extremely fast from hosting, a VPS or a CDN positioned close to users. Dynamic data is fetched on the fly by calling the backend through an API. This separation simplifies development and scaling, letting independent teams work on the interface and the server logic in parallel.