Free Online HTML Viewer
Write, paste, or edit HTML code and see the live preview instantly — entirely in your browser. No server, no signup, no data stored.
What is an HTML Viewer?
An HTML Viewer is a free online tool that lets you write or paste HTML code and instantly see how it renders in a browser — without needing to create files, install software, or set up a local server.
It's the fastest way to test HTML snippets, experiment with layouts, debug markup, or quickly preview email templates and web components. Just type your code on the left and watch the live output on the right.
Our HTML Viewer also supports inline CSS and JavaScript — so you can build fully interactive mini-pages, test animations, or prototype UI components on the fly.
#1
Most used markup language
Used by 100% of websites on the internet
5.3B
Web pages indexed
Every single one built with HTML
30+
Years old
HTML has powered the web since 1993
< 1s
Live preview speed
Instant rendering in our viewer
How to use the HTML Viewer?
Start viewing HTML output in seconds — no setup needed.
Write or Paste HTML
Type your HTML directly in the editor or paste existing code. The editor supports syntax highlighting for easier reading.
See Instant Preview
The live preview updates in real-time as you type. Switch to Split View to see editor and preview side by side.
Format & Edit
Use the Format button to auto-indent and clean up your HTML. Fix errors and experiment freely.
Copy or Download
Copy the HTML to your clipboard with one click, or download it as an .html file ready to use.
Everything you need in one tool
Built for developers, designers, students, and anyone who works with HTML.
Live Preview
See your HTML rendered in real-time as you type — no need to refresh or run anything manually.
Split View
Side-by-side editor and preview panes for a smooth, distraction-free coding experience.
Syntax Highlighting
Color-coded HTML syntax makes your code easier to read, write, and debug.
Auto Format
One-click HTML formatting to auto-indent and clean up messy or minified code.
100% Private
All processing happens in your browser. Your code is never sent to any server.
Download as HTML
Save your work as a .html file with one click — ready to use anywhere.
Fullscreen Preview
Expand the preview to full screen to test your layout at full viewport size.
Mobile Friendly
Works perfectly on smartphones and tablets — code and preview on the go.
Who uses this tool?
From beginners learning HTML to senior developers debugging code — useful for everyone.
Students & Learners
Learn HTML by experimenting in real-time — see the output of every tag instantly.
Web Developers
Quickly test HTML snippets, debug layouts, and prototype components without creating files.
UI/UX Designers
Preview HTML email templates, landing page sections, and component mockups instantly.
Teachers & Trainers
Demonstrate HTML concepts live in a classroom — no local setup required.
Bloggers & Writers
Preview HTML formatted content before pasting it into a CMS like WordPress.
QA Engineers
Test and validate HTML markup without spinning up a full development environment.
Get the most out of HTML Viewer
These tips will help you work faster and smarter.
Use Split View for best experience
Split view lets you edit and preview simultaneously without switching tabs.
Include <style> tags for CSS
Add <style>body { font-family: sans-serif; }</style> in your HTML for styled output.
Add <script> for JavaScript
JavaScript works in the preview — test animations, DOM manipulations and more.
Paste full HTML documents
Paste a complete <!DOCTYPE html> document to preview it exactly as a browser would render.
Download & share your work
Use the Download button to save your HTML and share it as a standalone file.
Use Format to debug messy code
Auto-formatting helps spot unclosed tags and structural errors at a glance.
Test responsive layouts
Use the fullscreen preview to see how your layout behaves at different widths.
Works with Bootstrap & Tailwind CDN
Include CDN links in your <head> to test component styles with popular frameworks.
Is this tool 100% safe to use?
Yes — completely safe. Your HTML code is never sent to our servers. The preview runs inside a sandboxed iframe that isolates it from the rest of the page.
- All rendering happens locally in your browser
- Your HTML code is never sent to any server
- No cookies, no tracking, no account required
- Preview runs in a sandboxed iframe
- Works offline once the page is loaded
- Be cautious running HTML+JS from unknown sources
Technical Architecture
Sandboxed iframe
IsolatedThe preview runs in a restricted iframe that isolates it from the parent page.
Zero Network Calls
Offline-ReadyYour HTML code never leaves the browser. Verify yourself in the Network tab.
No Storage
EphemeralRefreshing the page clears everything. No localStorage or sessionStorage used.
HTML Viewer: Complete Guide
What is HTML?
HTML (HyperText Markup Language) is the standard language for creating web pages. It uses tags like <h1>, <p>, <div>, and <img> to define the structure and content of a page. Every website you visit is built on HTML.
How do browsers render HTML?
Browsers parse HTML top-to-bottom, building a DOM (Document Object Model) tree. They then apply CSS styles and execute JavaScript to produce the final visual output. Our viewer uses an iframe to replicate this exact browser rendering behavior.
Can I use CSS in the HTML Viewer?
Yes — inline styles, <style> blocks, and even <link> tags to external CDN stylesheets all work. You can use Bootstrap, Tailwind, or any other CSS framework by linking their CDN in your <head> section.
Does JavaScript work?
Yes — JavaScript inside <script> tags runs inside the sandboxed iframe preview. You can test DOM manipulation, event listeners, animations, fetch calls (with CORS permitting), and more.
Is it safe to run unknown HTML?
The preview runs inside a sandboxed iframe which limits certain capabilities. However, always be cautious with HTML+JS code from unknown sources, as client-side scripts can still perform actions within the preview context.
HTML Best Practices
Always use semantic HTML elements (<header>, <main>, <section>, <article>). Include alt attributes on images for accessibility. Use heading hierarchy (h1 → h6) correctly. Keep your markup clean and well-indented for maintainability.
Frequently Asked Questions
Everything you need to know about the HTML Viewer.