HTML Beautifier
Re-indent and space out HTML markup to make it readable again.
How it works
HTML Viewer
Paste or type HTML and watch it render as you go. CSS and JavaScript work too, and you can check the page at laptop, tablet or phone width.
Preview Full width
Your rendered HTML will appear here.
The preview updates as you type. Your HTML stays in your browser.
- 01
Paste HTML into the editor, drop in an .html file or start from the sample.
- 02
Watch the preview update as you edit. Pick a width to check the responsive layout.
- 03
Turn JavaScript off to see the static page, open the preview full screen, or download your HTML.
About this tool
What is an HTML viewer?
An HTML viewer renders markup the way a browser would, so you can see a page, snippet or email template without saving a file or setting up a project. It's handy for checking code from a CMS, an AI assistant, a support ticket or a colleague before you use it.
The preview runs in a sandboxed frame, isolated from this site. Scripts in your HTML can run there but can't read your other tabs, cookies or saved data, and you can switch JavaScript off entirely to see the page as static markup.
Live preview
The page re-renders as you type, with no Run button to press.
Responsive widths
Switch between full width, laptop (1024px), tablet (768px) and phone (375px).
Safe sandbox
The preview is isolated from this site, and JavaScript can be turned off.
Full screen and download
Open the preview full screen, or save your HTML as a file.
FAQ
Frequently asked questions
Is it safe to preview HTML I didn't write?
The preview runs in a sandboxed frame with its own isolated origin, so scripts can't access this site, your cookies or other tabs, or navigate away from the preview. To be extra careful, turn off Run JavaScript and only the markup and styles render.
Why don't images or stylesheets with relative paths load?
Paths like images/logo.png point to files on the original site, which the viewer doesn't have. Use absolute URLs (https://…) for images, fonts and stylesheets you want to see.
Can I preview HTML email templates?
Yes. Paste the full template to see the layout, and use the phone width to check how it responds on mobile. Email clients render more strictly than browsers, so test in real clients before sending.
Is my HTML uploaded anywhere?
No. Your HTML is rendered in your browser and never sent to Instant.tools. If it links to external images, fonts or scripts, the preview loads those from their own servers, just like any web page.
Missing something?
Tell us the tool you wish existed.
Instant.tools grows from real requests. Describe the task you're stuck on and we'll consider building it next.