Embed the file extension lookup widget

The WhatFileType widget lets your visitors look up any file extension without leaving your page. It is a single lightweight iframe with no sign-up, and links each result to the full details. Paste one of the snippets below wherever you want it.

Live preview

Basic embed

Paste this where you want the widget to appear.

<iframe
  src="https://whatfiletype.com/widget"
  title="File extension lookup by WhatFileType"
  width="100%"
  height="240"
  style="border:0;max-width:440px;"
  loading="lazy"
></iframe>

Centered, responsive

Wrap it to cap the width and center it in a column.

<div style="max-width:440px;margin:0 auto;">
  <iframe
    src="https://whatfiletype.com/widget"
    title="File extension lookup by WhatFileType"
    width="100%"
    height="240"
    style="border:0;"
    loading="lazy"
  ></iframe>
</div>

Inline embed, with a real link

An iframe is a separate document: a link inside it lives on our page, not yours, and search engines treat it that way. If you would like the attribution to count as a normal link from your site, use this variant instead. It is the same frame with the credit line moved into your own HTML.

<!-- Attribution link lives in YOUR page's HTML, so it counts. -->
<div style="max-width:440px">
  <iframe
    src="https://whatfiletype.com/widget?theme=light"
    title="File extension lookup by WhatFileType"
    width="100%" height="240" style="border:0" loading="lazy"></iframe>
  <p style="font:12px/1.5 system-ui;margin:6px 0 0">
    File type lookup by
    <a href="https://whatfiletype.com/">WhatFileType</a>
  </p>
</div>

Keep the link plain. A nofollow or a redirect through a tracker turns the credit into decoration, and the whole reason this widget is free is that the credit is how people find the tool.

Parameters

Append these to the widget URL, for example /widget?ext=heic&theme=dark&compact=1.

Widget URL parameters
Parameter	Values	What it does
ext	any extension, with or without the dot	Opens with that format already looked up. Use it when the widget sits next to content about one specific format.
theme	light (default) or dark	Switches the widget to dark surfaces so it does not glow on a dark page.
compact	1	Drops the heading and tightens the padding. Fits a narrow sidebar at about 190px high instead of 240px.

The file signature reference

The second embed is the whole magic-numbers table: every documented file signature with its hex bytes, ASCII rendering, offset and the formats that share it, plus a filter box, in one self-contained frame. It suits a forensics write-up, a file-format course page or a developer wiki far better than a lookup box does.

It is published under a CC BY 4.0 licence, so you can also republish the table in your own markup as long as you credit WhatFileType and link back. Set the height to about 560px, or higher if you want more rows visible before the frame scrolls.

<iframe
  src="https://whatfiletype.com/widget/signatures"
  title="File signatures (magic numbers) reference by WhatFileType"
  width="100%"
  height="560"
  style="border:0;"
  loading="lazy"
></iframe>
<p><a href="https://whatfiletype.com/magic-numbers">File signature reference</a> by WhatFileType, CC BY 4.0</p>

Good to know

The widget is a static page, so it loads fast and never rate-limits.
Each result opens the matching WhatFileType page in a new tab, keeping visitors on your site.
A small "Powered by WhatFileType" link sits at the bottom. Please keep it, it is how people find the tool.
Set the iframe height to about 240px for the lookup widget, 560px for the table.
Both frames are plain static HTML with no framework and no third-party requests, so they will not slow your page down or track your readers.

Prefer raw data?

If you want to build your own interface, the same information is available from the free JSON API.