Web Engineering & Front-end

HTML Online Viewer

Edit, format, and preview HTML in real time with sandboxed execution, responsive device emulation for Desktop, Tablet, and Mobile, tag auditing, and instant minification. All code runs exclusively within your local browser tab, guaranteeing lightning performance and privacy for your UI layouts and components.

100% Local In-Browser Processing

Zero uploads to external servers. This tool retains a temporary draft in this device's local storage (localStorage) for convenience and continuity. You can delete saved data via the button on the right.

v2.2.0
Size: 0 B
Keys: 0
Depth: 0
Input JSON
Formatted JSON or TypeScript

100% Local In-Browser Processing

Zero uploads to external servers. This tool retains a temporary draft in this device's local storage (localStorage) for convenience and continuity. You can delete saved data via the button on the right.

v2.2.0

Developer Studio

Integrated into Developer Studio

Alongside the HTML viewer, access JSON formatting with TypeScript type generation, Unix timestamp converters, SHA-256 hashes, and JWT token inspection in one unified developer workstation.

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Frequently Asked Questions about HTML Online Viewer

Is my HTML code or data sent to any remote server?

No. All rendering, tag parsing, formatting, and sandboxed previewing happen entirely inside your browser's JavaScript engine. Zero code or telemetry is transmitted across the network.

How does responsive device emulation work?

The tool resizes the isolated iframe container to standard screen breakpoints (100% for Desktop, 768px for Tablet, and 375px for Mobile), allowing you to inspect media queries and responsive CSS rules without opening browser DevTools.

Can I open the rendered preview in a new tab?

Yes. You can press Alt+1 to pop out the live rendered HTML in an independent full-screen tab with an isolated sandbox, ensuring visual fidelity and interactive testing without leaving your editor.

Can I quickly inject third-party CSS or JS frameworks like Tailwind or Bootstrap?

Yes. The toolbar features one-click CDN inserters that inject official script and stylesheet links for Tailwind CSS, Bootstrap 5, FontAwesome, and Google Fonts into your document's head.