What Is an Embed Code? Guide for PDFs, Flipbooks, and Videos

What Is an Embed Code?

An embed code is a snippet of HTML that displays external content — a video, a PDF, a flipbook, a map, a tweet — inside your own web page. When a reader loads your page, the browser fetches the external content and renders it inline, as if it were part of your site.

The most common underlying technology is the <iframe> HTML element, which loads a separate web page inside a rectangular frame on your page.

The Basic Embed Code Structure

A typical embed code looks like this:

<iframe
  src="https://example.com/your-content"
  width="100%"
  height="600"
  allowfullscreen
  frameborder="0"
></iframe>

Every embed code includes four things:

• src — the URL of the content to embed.
• width and height — the dimensions of the frame (in pixels or percent).
• Permissions attributes — allowfullscreen, allow="autoplay", or sandbox flags that let the embedded content use certain browser features.
• Optional styling — frameborder, style attributes for visual polish.

When a reader opens your page, the browser sees the <iframe> tag, requests the URL in src, and renders the returned page inside the frame.

Where Embed Codes Come From

Every platform that supports embedding generates its own embed code. You copy it from the platform and paste it into your site:

• YouTube / Vimeo — Share button → Embed → copy iframe code.
• Google Maps — Share → Embed a map → copy the iframe.
• Twitter / X — Post → Embed this post → copy.
• FlipLink — every publication generates an embed code automatically, or use the free embed-pdf tool for one-off embeds without signup.

Each platform tunes the iframe's dimensions, permissions, and loading behaviour to its own content. You rarely need to modify the generated code — copy, paste, done.

How Does an Embed Code Differ From a Link?

A link sends the reader away from your page to the external content. An embed code keeps them on your page while showing the external content inline.

• Link: <a href="...">Watch video</a> — click to leave the page.
• Embed: <iframe src="..."> — content appears inline, no navigation.

This difference matters for bounce rate, reader engagement, and analytics. An embed lets you measure views without losing the visitor to another domain.

Embedding a PDF: Four Approaches

PDF embedding has evolved beyond the basic iframe. The four approaches, in order of simplicity:

1. Native <embed> or <object> tag

<embed src="document.pdf" type="application/pdf" width="100%" height="600" />

Works in desktop browsers but inconsistent on mobile. Readers see the browser's default PDF viewer, which varies by device and loses any interactivity.

2. Google Docs Viewer iframe

<iframe src="https://docs.google.com/viewer?url=YOUR_PDF_URL&embedded=true" width="100%" height="600"></iframe>

Free, works on mobile, but limited control over viewer appearance and no analytics.

3. PDF.js-based custom viewer

Ship Mozilla's PDF.js library on your site and embed a custom viewer. Full control over branding and behaviour but requires development work and ongoing maintenance.

4. Flipbook platform iframe (recommended for businesses)

<iframe src="https://your-flipbook-url" width="100%" height="600" allowfullscreen></iframe>

Upload the PDF to a flipbook platform, copy the generated embed code. Gets you clickable links, page-flip animation, analytics, and lead capture — no custom code, consistent mobile experience. See how to embed a PDF on your website for a full walk-through per platform.

Making Embed Codes Responsive

The default width="640" height="360" breaks on mobile. For responsive embeds, wrap the iframe in a container that preserves the aspect ratio:

<div style="position:relative; padding-bottom:141.4%; height:0;">
  <iframe
    src="..."
    style="position:absolute; top:0; left:0; width:100%; height:100%;"
    frameborder="0"
    allowfullscreen
  ></iframe>
</div>

The padding-bottom value sets the aspect ratio (141.4% = A4 portrait; 56.25% = 16:9 video; 75% = 4:3).

Security: What sandbox Does

Embedded content runs in the visitor's browser, so it can execute JavaScript, read cookies for its own domain, and even navigate the parent page. The sandbox attribute restricts what the embedded content can do:

<iframe src="..." sandbox="allow-scripts allow-same-origin allow-forms"></iframe>

Common flags:

• allow-scripts — permit JavaScript to run
• allow-forms — permit form submission
• allow-same-origin — treat content as first-party (needed for stored login state)
• allow-popups — permit target="_blank" links

For PDF embeds, the default (no sandbox) is usually fine unless you're embedding untrusted user-uploaded content.

Common Embed Code Mistakes

• Fixed pixel width. Using width="600" breaks on narrow mobile screens. Use width="100%" or the responsive wrapper.
• Missing allowfullscreen. Users cannot expand video or flipbook viewers to fullscreen.
• Stripped iframes by page builders. Some CMS editors (Squarespace Embed Block, WordPress without Custom HTML block) strip iframe tags. Always paste embed codes into a "Code" or "Custom HTML" block.
• Cross-origin errors in console. Some embeds need specific CORS headers from the source; if the embed looks broken, check the browser console.
• Broken preview in page editor. Many CMS editors do not render iframes in edit mode — always check on the published page, not in preview.

Frequently Asked Questions

Is an iframe the same as an embed code?

An iframe is one type of embed code — the most common one. Embed codes can also use <embed>, <object>, <video>, or platform-specific JavaScript widgets. For PDFs and flipbooks, iframes are the standard.

Does embedding a PDF slow down my website?

The iframe loads the PDF on demand, so it only affects page performance if the user scrolls to it. Use loading="lazy" on the iframe to defer loading until the embed is near the viewport.

Can I customise the appearance of embedded content?

You can control the outer frame (size, border, position) with CSS on the iframe. The inner content's appearance depends on the platform generating the embed code. FlipLink lets you apply brand colours and custom styling to the embedded viewer.

Does the embed code work on every website builder?

Any site that supports pasting raw HTML (WordPress Custom HTML, Wix HTML iframe, Squarespace Code Block, Webflow Embed, Shopify Custom Liquid, Notion /embed) accepts iframe embed codes. Some builders have additional platform restrictions — see our embed-per-platform guide for specifics.

How do I get an embed code for my PDF?

Use the free embed-pdf tool: upload a PDF, get an iframe embed code in seconds. No signup needed for one-off embeds.

Related Reading

• How to Embed PDF on Website: 5 Methods Compared
• How to Insert a PDF Into a Website, Document, or Email
• How to Embed Flipbook in Squarespace
• How to Embed Flipbook in Shopify
• What Is an Interactive PDF?