HTML

HTML is the markup language that structures web content with tags (e.g. headings, paragraphs, links). CSS styles its appearance. Clean, semantic HTML helps search engines, AI systems and screen readers understand content.

HTML stands for “Hypertext Markup Language”. It is a markup language used to structure a web page's content – text, images, links, forms. At its core, every web page consists of HTML. Two terms are central:

HTML element
HTML tag

Tags mark the beginning and end of a section in the document, for example <p> and </p> for a paragraph. An element comprises the tags and their content. Some elements consist of just a single tag without content, such as <br> for a line break or <img> for an image. Together, all the elements make up a page's HTML code, the so-called source code.

HTML is thus the fundamental language of the World Wide Web and also relevant for content creation. HTML is not a programming language but a markup language: it describes what content is, but doesn't execute any logic. JavaScript is added for logic and interaction, and CSS for design.

HTML gives content meaning, but no appearance. It defines which text is a heading, a subheading, a paragraph, a list or a link; CSS determines what it all looks like. It is precisely this meaning that matters for search engine optimisation: search engines and AI systems read the HTML code to understand a page's content. Clean, semantic HTML – with a logical heading structure, meaningful link texts, alt texts for images and elements such as <nav>, <main> or <article> – helps them do so. At the same time, it improves accessibility, as screen readers also rely on this structure.

Some examples of HTML elements

Document type declaration and root element: <!DOCTYPE html> followed by <html> … </html>

Head section with meta information such as page title and description: <head> … </head>

First-level heading: <h1> Heading </h1>

Paragraph: <p> Text </p> and line break: <br>

Page title that appears in the search results: <title> Page title </title>

HTML in practice

HTML is continuously developed by the WHATWG (Web Hypertext Application Technology Working Group) as the “HTML Living Standard”; the former version name HTML5 has been absorbed into it. All modern browsers support it. In everyday work, hardly anyone writes HTML by hand any more: shop systems such as Shopware and Shopify or a CMS generate the code from templates, and editors design content using visual editors with buttons for headings, lists or links – similar to a word processor. Many editors also offer an HTML view in which the code can be edited directly. For SEO, it's still worth looking at the source code: are the heading structure, title and description correct, and is important content directly in the HTML or only loaded later via JavaScript?

HTML is styled with CSS. Style sheets can be placed directly in the HTML document (internal style sheet) or – more commonly – included as separate files. They control colours, fonts, spacing and layout.