I wrote a ruby gem that wraps the HTML tidy executable for local HTML validation. Disclaimer: It is vetted with the HTML 5 compatible tidy version, but I haven&#x27;t tried it out with this new version yet. Pull requests welcome.<p><a href="https:&#x2F;&#x2F;github.com&#x2F;ericbeland&#x2F;html_validation" rel="nofollow">https:&#x2F;&#x2F;github.com&#x2F;ericbeland&#x2F;html_validation</a>