HTML Viewer Online

What is HTML Viewer Pro?

ToolsViewer's HTML Viewer Pro is a free html viewer and HTML previewer: open or paste HTML (including HTML5), edit with a live HTML preview, then format, minify, validate, or diff — privately in your browser, with no signup.

Preview runs in a sandboxed iframe on your device. Markup is not uploaded for editing or preview unless you copy or export it. For HTML email client previews, use Email Viewer instead.

Price
Free
Account
Not required
Runs in
Your browser
Drafts
Stay local

How to use it

Paste or import HTML, preview live, then tidy and export.

  1. Input your HTML

    Paste code, type in the editor, or import a .html / .htm file.

  2. Watch the live preview

    The sandboxed preview updates as you edit, including CSS and simple JavaScript.

  3. Clean, compare, export

    Format, Minify, Validate, Diff — then copy or download when you are done.

Common use cases

Preview, debug, prototype, and tidy markup without an IDE.

  • Preview and debug

    See markup render before you publish. Isolate broken HTML or CSS with instant preview feedback.

  • Prototype and tidy

    Try UI pieces with live updates. Format, minify, validate, or diff — or edit HTML, CSS, and JS in resizable panes.

  • Honest limits

    Not a full IDE or cloud workspace. External scripts still follow browser CORS. No account sync or remote hosting.

Features in the workspace

Split-screen live preview, HTML5 pages, format and minify, validate and diff, inspect element linking, and HTML / CSS / JS panels. Students, creators, and developers get a private HTML editor with preview — without installing an IDE or signing up.

Prefer a walkthrough? Open the HTML Viewer Pro guide or browse the HTML Viewer Pro blog. Related apps live on the Tools Viewer homepage. Need a PDF of your page? Convert HTML to PDF online, or read HTML to PDF with JavaScript, HTML to PDF libraries & APIs, how to embed a PDF in HTML, and how to convert PDF to HTML (ToolsViewer does not convert PDF → HTML).

Related tools

Guides & articles

Frequently asked questions

What is an HTML viewer online?

An HTML viewer online lets you paste or open HTML and see the rendered page in your browser. ToolsViewer’s HTML Viewer Pro also includes a live editor plus format, minify, validate, and diff tools.

What is an HTML previewer?

An HTML previewer shows how your markup looks as a page while you edit. HTML Viewer Pro is a free HTML previewer with a side-by-side live preview for HTML, CSS, and simple JavaScript.

Can I preview HTML5 code online?

Yes. Paste or import HTML5 markup and watch the HTML5 preview update in a sandboxed frame — useful for tags, forms, and media without installing software.

What is a good HTML viewer?

A good HTML viewer updates as you type, keeps code private in the browser, and offers more than preview — including format, minify, validate, and diff. That is what HTML Viewer Pro is built for.

Is this HTML viewer online free?

Yes. HTML Viewer Pro on ToolsViewer is free with no signup for preview, edit, format, minify, validate, and diff.

Is my HTML uploaded to a server?

No. Preview and editing run locally in your browser. Markup stays on your device unless you export or copy it yourself.

Is HTML Viewer Pro a full IDE?

No. It is a browser HTML/CSS/JS preview and toolkit — not a cloud IDE or team workspace. There is no account sync or remote project hosting.

How do I open an HTML file online?

Click Import and choose a .html or .htm file. It loads in the editor with a live preview so you can open an HTML file online without installing software.

How do I preview an HTML file in my browser?

Import the file in HTML Viewer Pro, or paste the markup. The live HTML preview updates as you edit — no local server required for typical pages.

How do I open an HTML viewer in Chrome?

Open this page in Chrome or any modern browser, then paste or import HTML. Preview runs in a sandboxed frame — no extension required.

Can I use it as an online HTML editor with preview?

Yes. Edit HTML on the left and watch the live preview update on the right — including CSS and simple JavaScript. It works as a free HTML editor with preview.

Can I use it as an HTML online compiler?

Yes for typical pages. Paste or import HTML with CSS and JavaScript and run it in the sandboxed preview without installing an IDE.

Will it run my JavaScript?

Yes for typical inline and same-document scripts. Preview runs in a sandboxed iframe. External scripts still follow normal browser CORS rules.

Does it support HTML, CSS, and JavaScript?

Yes. Paste a full document or use HTML/CSS/JS panels to edit each language separately with a shared live preview.

Can I format and minify HTML online here?

Yes. Use Format to beautify markup, Minify to shrink it, and Validate to catch common HTML issues.

Can I see a DOM outline of my HTML?

Yes. Use Structure to list elements with document stats (counts, depth, links, images, and more). Parsing runs in your browser via DOMParser.

Does it include an HTML diff checker?

Yes. Use Diff to compare two versions of your markup before you export.

Can I export HTML to PDF, PNG, or JPG?

Yes. Use Export to download the source HTML or a PDF/PNG/JPG snapshot of the rendered page. Conversion runs in your browser from a canvas rasterization — it is not a print-engine or vector PDF, and nothing is uploaded.

Do I need an account to use the HTML viewer?

No. Optional preferences such as theme may be saved in local storage on your device only.

Should I use HTML Viewer Pro for email HTML?

For webpage HTML, CSS, and JS — yes. For email client simulations, MJML, and pre-send QA, use ToolsViewer’s Email Viewer instead.