NewAI Coding Agent Skill for Claude Code & Codex

HTML tester & code runnertest and run HTML online

Test HTML snippets and run code in an instant browser sandbox. Paste your markup, execute JavaScript and CSS in real time, and share or export the test results.

No signup requiredInstant live renderingShare as Link, QR, PNG or PDF

<!doctype html>
<html lang="en">
  <head>
    <meta charset="utf-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1" />
    <style>
      body {
        margin: 0;
        font-family: Inter, system-ui, sans-serif;
        min-height: 100vh;
        display: grid;
        place-items: center;
        background: #f8fafc;
        color: #0f172a;
        padding: 24px;
        box-sizing: border-box;
      }

      main {
        width: min(520px, 100%);
        border: 1px solid #dbeafe;
        border-radius: 16px;
        background: white;
        padding: 32px;
        box-shadow: 0 18px 48px rgba(15, 23, 42, 0.08);
        text-align: center;
      }

      h1 {
        margin: 0;
        font-size: 48px;
        line-height: 1.1;
        color: #2563eb;
      }

      p {
        margin: 16px 0 0;
        color: #475569;
        font-size: 18px;
      }
    </style>
  </head>
  <body>
    <main>
      <h1>Hello World</h1>
      <p>This is a simple HTML preview example.</p>
    </main>
  </body>
</html>

<!doctype html>
<html lang="en">
  <head>
    <meta charset="utf-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1" />
    <style>
      body {
        margin: 0;
        font-family: Inter, system-ui, sans-serif;
        min-height: 100vh;
        display: grid;
        place-items: center;
        background: #f8fafc;
        color: #0f172a;
        padding: 24px;
        box-sizing: border-box;
      }

main {
        width: min(520px, 100%);
        border: 1px solid #dbeafe;
        border-radius: 16px;
        background: white;
        padding: 32px;
        box-shadow: 0 18px 48px rgba(15, 23, 42, 0.08);
        text-align: center;
      }

h1 {
        margin: 0;
        font-size: 48px;
        line-height: 1.1;
        color: #2563eb;
      }

p {
        margin: 16px 0 0;
        color: #475569;
        font-size: 18px;
      }
    </style>
  </head>
  <body>
    <main>
      <h1>Hello World</h1>
      <p>This is a simple HTML preview example.</p>
    </main>
  </body>
</html>

Live Preview

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HTML Code Runner & Tester

Run and test HTML code snippets without an IDE

Use ViewHTML when you need a fast, isolated browser runner for a component, email block, generated section, or one-off HTML idea without opening a full IDE or terminal.

Run HTML code instantly

Paste any HTML block and see live execution immediately with CSS and JavaScript enabled.

Inspect in fullscreen

Use fullscreen preview when a snippet needs responsive room or an uncluttered testing surface.

Export test results

Save the rendered output as a PDF or image for bug tickets, approval notes, or documentation.

How it works

Test and run HTML in three steps

Paste code

Add the HTML, CSS, or JavaScript code you want to test.

Run in browser

The online HTML runner executes your code with live interactive preview.

Share or save

Create a shareable preview link, PNG screenshot, or PDF document.

Use cases

What to test with an HTML code runner

Use this runner for fast validation before HTML is sent, merged, published, or reused.

Run HTML code snippets in a safe browser sandbox

Test interactive JavaScript and CSS styling online

Run AI-generated HTML code from ChatGPT, Claude, or Cursor

Validate landing page sections and UI components visually

Create high-resolution screenshots of rendered HTML for tickets

Share a live rendered HTML test result via a preview link

HTML Workflows

Dedicated HTML inspection & testing tools

Each page is focused on a specific task: opening saved HTML files, testing snippets, or live code preview.

Free online HTML viewer

Use this free online HTML viewer to preview HTML, CSS, and JavaScript code instantly. Open .html files, inspect live rendering side-by-side, and share or export easily.

HTML file viewer

Free online HTML file viewer to open, view, and inspect .html and .htm files directly in your browser. No local server required. Fast live rendering with export options.

HTML previewer online

Paste HTML code and preview the rendered page instantly. A free online HTML previewer for snippets, prototypes, CSS checks, and AI-generated HTML.

FAQ

Frequently asked questions

What is an HTML runner and tester?

An HTML runner is an online tool that executes HTML, CSS, and JavaScript in a secure browser sandbox, displaying the rendered page output side-by-side with your code.

Does this HTML code runner support JavaScript?

Yes. The HTML runner executes standard client-side JavaScript, DOM manipulation, animations, and inline styling within a secure browser sandbox.

Can I test partial HTML snippets?

Yes. You can test complete HTML5 documents or isolated fragments like email cards, navigation bars, and buttons. ViewHTML renders whatever code you provide.

How do I share my HTML test results?

Once your code runs as expected, click Link to generate a public preview URL or export the output directly as a PNG screenshot or PDF document.