HTML Viewer

Paste HTML and instantly preview how it renders in a sandboxed frame

HTML Input

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Preview

Preview HTML safely without saving a file

When you've copied an HTML snippet from a docs page, an email template, or AI output, opening it as a real browser page is the quickest way to see how it actually renders. A sandboxed viewer renders the markup in an isolated frame so you don't have to write a temporary file or launch a server.

Use the viewer when you need to

Preview an email template

Render the HTML to spot broken layouts, missing inline styles, or unsupported tags before sending.

Inspect copied or AI-generated HTML

Quickly see how a snippet renders without committing it to your project or local filesystem.

Verify markup from documentation

Drop sample HTML from API docs into the viewer to confirm what the upstream actually produces.

How to preview HTML quickly

1
Paste your HTML markup into the editor.
2
Watch it render in the sandboxed preview frame instantly.
3
Adjust the markup and re-preview as you iterate.

Keep going

Edit HTML, CSS, and JS

Use the full playground when you need to experiment with styles and behavior too.

Format the markup

Beautify the snippet before pasting it into your codebase.

Format embedded CSS

Clean up the styles inside your HTML for easier review.

Format embedded scripts

Pretty-print the JavaScript inside your HTML snippet.

Common HTML-preview workflows

Test an email template

Render the HTML in a sandboxed frame to verify the layout before pasting it into your email tool.

Validate AI-generated HTML

Preview model output to confirm the structure matches the design before integrating.

Show a teammate a markup question

Render a snippet and screenshot the result instead of describing the rendering issue in prose.

Часто задаваемые вопросы

The viewer is read-only: paste HTML and see it render. The HTML Editor lets you edit HTML, CSS, and JavaScript together with a live preview. Pick the viewer when you only need to render existing markup.

Yes. The HTML renders inside a sandboxed iframe, which isolates it from the rest of the page. Scripts in the previewed HTML can run but cannot access JSONTech or your other tabs.

Yes. Paste your email's HTML body to preview how it renders. Note that email clients apply their own restrictions on top of the sandbox, so the preview is a best-case rendering.

External stylesheets, scripts, and images load if their URLs are public and CORS-friendly. Resources that require authentication or specific origins may not render.

No. The HTML is rendered locally in your browser. Nothing is uploaded to JSONTech or stored on any server.