HTML is the markup language that structures every web page — it defines headings, paragraphs, links, images, and media using a system of tags that browsers render into visual content.
Use caution
Type Code
By W3C / WHATWG
MIMEtext/html
Drop any file to identify it
We read file headers, not extensions. Nothing gets uploaded.
HTML is the markup language that structures every web page — it defines headings, paragraphs, links, images, and media using a system of tags that browsers render into visual content. The bones of every website. It is not a programming language, and it does not need to be. 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: 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. View Source on any page and there it is.
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
FREEAll
Any text editor
FREEAll
VS Code
FREEAll
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.