How to Use the unfiltered_html Capability in WordPress

Unfiltered Html Header

In this tutorial, I'm going to introduce you to the unfiltered_html permission. This permission is a security feature in WordPress that prevents users from using tags such as iframe and embed, plus also more advanced code such as Javascript.

This unfiltered_html permission could be very dangerous in the wrong hands, so please don't give this permission to any users you do not trust. WordPress has disabled this permission for most users because they rarely need it.

How does the unfiltered_html permission work?

Let's see the unfiltered_html permission in action.

In the post below, I've created a Paragraph block. I'm using the Gutenberg editor:

A WordPress post to test the unfiltered_html permission

In the settings for this paragraph block, I click the “Edit as HTML” option:

Edit as HTML option for Gutenberg blocks to test the unfiltered_html permission

Now in the HTML version of the block, I enter the HTML code for an iframe:

Trying to use iframe in an HTML block in WordPress to test unfiltered_html

When I try to save this post, or edit the block visually, WordPress will complain with the message: “This block contains unexpected or invalid content.” This happens because I do NOT have the unfiltered_html permission.

This block contains unexpected or invalid content. This message shows if you do not have the unfiltered_html  permission

If you click “Resolve”, WordPress will try to convert the code to something safer. However, the code shown below in the “After Conversion” area will not work:

Resolve unexpected or invalid content in WordPress. This happens if you do not have the unfiltered_html  permission.

If you want to add code like this to WordPress, you do need the unfiltered_html permission.

Also, if you do want to add detailed code blocks to WordPress, check out our guide on showing code with Gutenberg.

How to give users the unfiltered_html permission

If you use the PublishPress Capabilities plugin, you can enable or disable this permission for each user role.

  • Go to “Capabilities” in your WordPress admin area.
  • In the top-right corner of the screen, load the user role that you want to customize. In this image below, I’ve chosen the “Editor” role:
Choose the Editor role in WordPress to give the unfiltered_html permission

In the center of the screen, you can now set the permissions. If you want to allow people in the Editor role to create posts, check the “unfiltered html” box. Click the blue “Save Changes” button to finish,

Giving the unfiltered_html  permission in WordPress

If you want to set these permissions across a multisite network, follow these instructions. On WordPress multisite networks, only Super Admins have the unfiltered_html permission.

Finally, it's worth noting that I gave the example for unfiltered_html in a Post, but the permissions also works inside other post types, plus comments and widgets.

The technical details behind unfiltered_html

The unfiltered_html permission works by running your code through the wp_kses function. I found this to be a good guide to wp_kses.

More key WordPress permissions

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