Frontend Concepts, Explained
Interactive, visual explanations of concepts every frontend developer runs into early on.
What's covered
The Core Concepts
Each idea paired with an interactive demo.
The DOM
The live tree the browser builds from your HTML.
Responsiveness
Making layouts adapt to any screen size.
Components
Why we build UIs out of reusable pieces.
State
How apps remember things that change.
API Calls
How the frontend asks a server for data.
Frameworks
A pre-built foundation that handles the repetitive parts of building an app.
Accessibility
Making sure the UI works for everyone.
Changelog
Recently Shipped
A few of the latest improvements.
- 2026-07-24
Consistent theming
A scroll-aware light/dark toggle and a token-based palette that keeps every page readable in both modes.
- 2026-07-22
Keyboard-friendly demos
Every interactive demo now works fully from the keyboard, including the drag-to-resize viewport.
- 2026-07-21
Clearer explanations
All seven concepts rewritten for clarity, each closing with a single-sentence takeaway.
What's next
How to Approach a Component
Breaking down real UI challenges.
Coming soonHave a suggestion or found something to improve?
Open an issue on GitHub