Free tool

HTML viewer.

Paste HTML or drop an .html file and watch it render — CSS, JavaScript and charts included. It runs entirely in your browser. When it looks right, turn it into a link people can open and comment on.

What the viewer does

• Renders full documents and fragments — inline <style>, inline <script>, SVG, canvas charts, and libraries loaded from jsDelivr, unpkg or cdnjs.
• Opens local .html files without a server: drop the file on the editor or use Open file.
• Checks layout at desktop, tablet (768 px) and phone (390 px) widths.
• Runs the page in a sandboxed iframe with no access to this site, and sends nothing to a server.

When the preview is blank

Usually one of two things. The page references files that sit next to it — a stylesheet, an images folder — and a single pasted document doesn’t have them. Or it’s an app shell that loads its data with fetch() at runtime, as Allure and Playwright reports do. For the first, create a report and upload the whole folder or a .zip — the references get rewritten to the uploaded copies. For the second, use the tool’s single-file export. More in someone sent me an HTML file and the troubleshooting guides.

Questions

How do I view an HTML file online?

Paste the markup into the editor on this page, or drop the .html file onto it. The page renders on the right as you type — styles, inline scripts and charts included. Nothing installs and nothing uploads.

Is my HTML uploaded anywhere?

No. The preview is built in your browser and rendered in a sandboxed iframe on this page. The HTML only leaves your machine if you click “Get a shareable link” and create a report.

Is it safe to preview HTML I didn't write?

The preview runs with scripts allowed but without same-origin access, so the page can't read this site's cookies, storage or DOM, open popups, or navigate the tab. That's a containment boundary, not a malware scanner — don't paste files from senders you don't trust.

Why are images or styles missing from the preview?

The HTML refers to files next to it — images/logo.png, style.css — and a pasted document has no folder. Either inline those assets, or create a report and upload the whole folder or a .zip: Comma uploads the siblings and rewrites the references to point at them.

Why is my report blank here and when I open it locally?

Reports like Allure, Playwright and most coverage UIs are a small shell that loads its data with fetch() at runtime. A pasted or local copy has nowhere to fetch from. Use the tool's single-file export if it has one; see the troubleshooting guides for the per-tool fix.

How do I share the HTML as a link?

Click “Get a shareable link”. You'll land in the Comma editor with the HTML already loaded; save it and you get a URL you can make private, invite-only, or open to anyone with the link — and readers can leave comments anchored to the exact paragraph or chart. Comma is free.

Related: upload an HTML file and get a link · host an HTML file · comment on HTML · report types