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.html

What is a .html file?

HTML is the markup language that structures every web page — headings, paragraphs, links, images, and media defined in a system of tags.

Use caution
Type Code
By W3C / WHATWG
MIME text/html

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What is it

You right-clicked on a web page and selected "View Source." Everything you see — the angle brackets, the tags, the structure — is HTML. It's not a programming language and it doesn't need to be. HTML is a markup language: a way of annotating text so browsers know what's a heading, what's a paragraph, what's a link, and what's an image.

Tim Berners-Lee wrote the first version in 1991 with barely 20 tags, and the web grew from there. Today's HTML5 handles video, audio, canvas drawing, semantic structure, and accessibility, but the core idea hasn't changed in thirty years. You write content in angle brackets and a browser turns it into something visual. Every website you've ever visited — from a personal blog to a billion-dollar application — is HTML at its foundation.

Any browser renders HTML. Any text editor writes it. VS Code is the standard for web development. You can create a working web page with nothing but a text file and a browser — no server, no build tools, no framework. For learning web development, HTML is where everyone starts, and it remains relevant no matter how complex the stack above it becomes.

Technical details
Full Name
HyperText Markup Language
MIME Type
text/html
Developer
W3C / WHATWG
Magic Bytes
N/A
Safety
.html requires caution. HTML files can contain embedded scripts. Open files from unknown sources in a browser's sandbox, not as local files with full permissions.
What opens it
Any web browser
FREE All
Any text editor
FREE All
VS Code
FREE All
FAQ
What is the difference between HTML and HTM?
Nothing meaningful. HTM is a relic from the days when file extensions were limited to three characters (MS-DOS, early Windows). HTML and HTM are identical in content and behaviour. Modern systems use .html by convention.
How do I open an HTML file?
Double-click it and it opens in your default web browser, rendered as a visual page. To see or edit the source code, right-click and open with any text editor (VS Code, Notepad, TextEdit). In a browser, View Source (Ctrl+U / Cmd+U) shows the raw HTML.
Is HTML a programming language?
No. HTML is a markup language — it describes the structure and content of a document, but it cannot perform logic, make decisions, or run calculations. Programming requires languages like JavaScript, Python, or C. HTML is often learned alongside CSS (styling) and JavaScript (interactivity) as the foundation of web development.
Related formats
.css
Cascading Style Sheets
.js
JavaScript
.php
PHP Script