Free HTML Preview Tool

Free HTML Viewer Online

An HTML viewer online is a browser tool that turns pasted HTML into a rendered page preview instantly. Use this free Zap Code viewer to edit markup, test CSS and simple JavaScript, compare responsive widths, and save a working HTML file.

Open HTML viewer Build with Zap Code

Current HTML

Characters: 1,330
Lines: 60
Tags: 12
Scripts: 0

The preview runs inside a sandboxed iframe so code experiments stay isolated from the rest of the page.

HTML editor

Paste a full document or a snippet.

<!doctype html>
<html lang="en">
  <head>
    <meta charset="utf-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1" />
    <title>My First Web Page</title>
    <style>
      body {
        margin: 0;
        font-family: system-ui, sans-serif;
        background: linear-gradient(135deg, #fdf2f8, #cffafe);
        color: #111827;
      }

main {
        min-height: 100vh;
        display: grid;
        place-items: center;
        padding: 32px;
      }

article {
        max-width: 620px;
        border: 4px solid #111827;
        border-radius: 24px;
        background: white;
        padding: 32px;
        box-shadow: 12px 12px 0 #00bcd4;
      }

h1 {
        margin: 0;
        font-size: clamp(2rem, 8vw, 4rem);
      }

p {
        font-size: 1.15rem;
        line-height: 1.7;
      }

button {
        border: 0;
        border-radius: 999px;
        background: #e040fb;
        color: white;
        font-weight: 800;
        padding: 14px 20px;
      }
    </style>
  </head>
  <body>
    <main>
      <article>
        <h1>Hello, builder!</h1>
        <p>Edit the HTML on the left and watch this preview update instantly.</p>
        <button onclick="this.textContent = 'You clicked it!'">Click me</button>
      </article>
    </main>
  </body>
</html>

12 tags, 1 style blocks, 0 script blocks

Rendered preview

Test the page at common viewport widths.

How to use the HTML viewer

1
Paste or write HTML
Add a full HTML document or a smaller snippet into the editor. The preview can render HTML, CSS, and simple JavaScript.
2
Preview the rendered page
The iframe updates as you type so you can check headings, layout, styles, and button behavior without saving a file.
3
Test responsive widths
Switch between desktop, tablet, and mobile widths to see whether your HTML page still reads well on smaller screens.
4
Copy or download the result
Copy the finished markup or download it as an HTML file when you are ready to use it in a project or lesson.

HTML viewer FAQ

What is an HTML viewer online?

An HTML viewer online is a browser tool that renders pasted HTML so you can see the page output immediately. It is useful for checking markup, CSS, and small JavaScript examples without creating a local file.

Can this HTML viewer run CSS and JavaScript?

Yes. The preview renders inline CSS and simple JavaScript inside a sandboxed iframe, which keeps the test page separate from the rest of Zap Code.

Do I need a complete HTML document?

No. A complete document works best, but you can also paste a small HTML snippet. The browser will still render the snippet in the preview frame.

Is an HTML viewer good for beginners?

Yes. Beginners can connect each tag and style rule to the visual result immediately, which makes HTML structure easier to understand than reading code alone.

Can I download the HTML I create?

Yes. Use the download button to save the current editor content as an .html file, then open it locally or keep editing it in another code editor.

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Free HTML Viewer Online

HTML editor

Rendered preview

How to use the HTML viewer

Paste or write HTML

Preview the rendered page

Test responsive widths

Copy or download the result