In WordPress, sponsored links and nofollow links are essential for SEO optimization and content compliance. Sponsored links are typically used for affiliate or paid promotions, requiring the rel=”sponsored” attribute to comply with Google’s guidelines and avoid being seen as link selling. Nofollow links use the rel=”nofollow” attribute to instruct search engines not to pass page weight, commonly applied to external links, comments, or user-generated content to prevent spam from affecting site rankings.
Highlighting these links (e.g., with colors or background in the editor) helps content creators quickly identify and manage them, especially when handling large numbers of posts in the Gutenberg editor. This prevents overuse of such links, maintaining the site’s SEO health.

Why highlight these links?
Understand their roles first: Nofollow links do not pass SEO value, suitable for uncertain sources; sponsored links explicitly mark paid content for transparency. Highlighting allows you to spot links needing adjustments at a glance during post editing, such as removing excess nofollows or adding missing sponsored attributes. Per Google’s 2019 update, sponsored complements nofollow for precise identification of paid links.

Method 1: Use CSS to Highlight in Gutenberg Editor (Recommended Simple Method)
WordPress’s Gutenberg editor (block editor) supports custom CSS to style links based on their rel attributes. This is the most straightforward approach without plugins.

Log in to WordPress Dashboard: Go to “Appearance” > “Customize” > “Additional CSS”. Or, for editor-only, use “Editor” > “Styles” > “Colors” or add CSS directly.

Add CSS Code: Paste the following code in the CSS area. This adds a yellow background and black text highlight for links with rel=”sponsored” or rel=”nofollow” (customize colors as needed):
text.editor-styles-wrapper a[rel~=”sponsored”],
.editor-styles-wrapper a[rel~=”nofollow”] {
background: #FFFF00 !important;
color: #000 !important;
padding: 2px 4px;
border-radius: 3px;
}

.editor-styles-wrapper ensures it only affects the editor, not the frontend.
~= is a CSS attribute selector matching values containing the specified attribute (e.g., rel=”nofollow sponsored” will match).

Save and Test: Save changes, then edit a post with such links. You’ll see the highlight effect, e.g., affiliate links in yellow background for easy scanning.

This method uses attribute selectors and is simple and efficient. For the Classic Editor, add the CSS to your theme’s style.css, targeting the .wp-editor class.

Method 2: Use Plugins for Automated Highlighting and Attribute Addition
If manual CSS isn’t enough, plugins can extend functionality. They not only highlight but also simplify adding sponsored/nofollow.

Recommended Plugins:

Gutenberg Highlight Sponsored Nofollow Links: Designed for Gutenberg, auto-adds the CSS above. Highlights sponsored and nofollow links. Install and activate—no extra setup needed.
All in One SEO (AIOSEO) or Rank Math: These SEO plugins provide direct nofollow and sponsored options in the link insertion interface. Combine with custom CSS for highlighting.

Install AIOSEO: Go to “Plugins” > “Add New” > Search “AIOSEO” > Install and activate.
In post editing, highlight text > Click link icon > Check “Add rel=’nofollow’” or “sponsored” in settings.

Add Link Attributes and Highlight with Plugins:

Create Link: Highlight anchor text, click link button, enter URL.
In advanced options, select rel=”sponsored” (for paid links) or rel=”nofollow” (for general external links).
Pair with Method 1’s CSS for highlighting.
For bulk, plugins like Tasty Links apply attributes to existing links with one click.

Plugins’ advantage is automation; e.g., AIOSEO auto-adds nofollow to affiliate links and reports potential issues via dashboard.

Practices and Notes

When to Use: Always add sponsored for affiliate/paid links; use nofollow for uncertain external links. Avoid overuse to prevent diluting site authority.
SEO Impact: Proper tagging helps Google understand intent, avoiding penalties. Audit links regularly with tools like Google Search Console.
Testing: Test CSS highlighting on a staging site to ensure no mobile issues.
Updates: WordPress core supports sponsored in the block editor since 5.3; keep plugins updated.

With these methods, you can easily manage and highlight sponsored and nofollow links in WordPress, improving content quality and SEO performance.