Term · Web & development
Frontend and backend
In web and app development, the frontend is the part users see and interact with — pages, buttons, forms, animations — running in the browser or on the phone. The backend is the server side — databases, business logic, integrations, authentication — that the frontend talks to, usually through an API.
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Explained
What each includes
Frontend:
- layout and visual design implemented in HTML, CSS and JavaScript (or a mobile framework);
- interaction: forms, filters, navigation;
- rendering content for users and search engines;
- performance on the user's device.
Backend:
- storing and retrieving data;
- business rules: prices, permissions, workflows;
- integrations with payment providers, CRM, 1C and other systems;
- security: authentication, authorisation, validation;
- background jobs: emails, notifications, synchronisations.
Why the distinction matters
- Skills: frontend and backend development require different expertise; a project usually needs both.
- Reuse: one backend can serve a website, a mobile app and a bot.
- Security: rules must be enforced on the backend, because anything in the frontend can be bypassed.
- Estimates: a simple-looking screen may hide significant backend work, and vice versa.
"Full-stack" developers work on both sides.
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FAQ
Frequently asked questions
Does a simple website have a backend?
A static site may not; any site with forms, accounts, a CMS or integrations does.
Can the frontend and backend be built by different teams?
Yes, with a clearly defined API between them.