HTML
HyperText Markup Language — the standard language for structuring web pages. Every website is built on HTML. It defines the content and structure (headings, paragraphs, links, images, forms) that browsers render. HTML5 added semantic elements, video/audio, and canvas.
Tim Berners-Lee · Invented HTML and the World Wide Web at CERN in 1989
- Every web page, always.
- Content-first sites where SEO and accessibility matter.
- Native mobile/desktop UIs (use platform UI frameworks).
- Anything that isn't a document/page.
Definition
HTML uses tags (elements) to mark up content: <h1> for headings, <p> for paragraphs, <a> for links, <img> for images, <form> for inputs. The browser parses HTML into a DOM tree and renders it. HTML5 added semantic tags (<header>, <nav>, <article>, <section>), native media (<video>, <audio>), canvas, and web APIs.
Why it exists
To provide a shared, declarative way to describe document structure that any browser can render, so the web works across devices and vendors.
How it works
You write .html files (or generate them server-side). The browser downloads HTML, parses it into a DOM tree, and renders it. CSS styles the DOM; JavaScript manipulates it. HTML is the skeleton every web page is built on.
Scaling limits
HTML itself doesn't scale-limit — it's static markup. The challenge is generating it efficiently (SSR, SSG) and keeping it accessible and semantic.
Cost shape
Free. HTML is a standard, no licensing or runtime cost.
Alternatives
- Markdown — Simpler for content authors but needs conversion to HTML.
- WYSIWYG editors — Visual editing but output may not be semantic HTML.
Failure modes
- Non-semantic div soup hurting accessibility and SEO.
- Missing alt text on images.
- Invalid nesting breaking rendering.