WP-Validate indexes your site, collecting all the blog posts, pages and other published content, and submits it to the W3C’s HTML Validator, which then returns the response.
WP-Validate then lists the valid pages, and the invalid pages, with a link to the specific validator URL.

WP-Validate

WP-Validate collects all the pages on your site and runs them through the W3C's HTML Validator.

Sumit Malviya

The Nofollow External/Outbound Link plugin is designed to enhance your website’s SEO capabilities by automatically adding a rel=”nofollow” attribute to external hyperlinks. This simple yet powerful tool helps safeguard your site from potential outbound link penalties while maintaining optimal link equity flow within your content.
With no complex backend configurations required, this plugin seamlessly integrates into your WordPress site. Upon activation, it works silently in the background, applying the rel=”nofollow” attribute to all external links across your website. This proactive approach ensures that search engine crawlers recognize these links as non-endorsements, helping you maintain control over your site’s link profile.
Ideal for SEO practitioners, website administrators, and content creators alike, the Nofollow External/Outbound Link plugin offers peace of mind and enhances your site’s SEO performance effortlessly.
No backend setting required:
Just install and activate you don’t need to do any setting configuration 
from the backend.
It automatically applies on the external links.

Nofollow External/Outbound Link (SEO)

The Nofollow External/Outbound Link plugin is designed to enhance your website's SEO capabilities by automatically adding a rel="nofollow&qu …

WP-Validate vs Nofollow External/Outbound Link (SEO)