You are looking at a page of your site and you want to know, right now, whether its SEO basics are in place. SEO Debug Bar adds a small button at the bottom right of your pages. Click it, and you get an audit of the page you are on, with a color for each point and a score.

The 27 checks

Title tag length
Meta description
Meta robots and X-Robots-Tag (is the page indexable?)
Open Graph tags: title, description, image, url, price and currency (for product pages)
Twitter card
Canonical URL
Favicon
Headings: number of H1, H2 and H3, and a wrong heading structure (for example an H4 straight after an H2)
Empty image alt attributes and empty link title attributes
Sitemap (the WordPress sitemap or sitemap.xml) and robots.txt
Inline and external style files, third-party styles
Inline and external script files, third-party scripts
Outbound links

Who sees the bar

Logged-in administrators, on every page of the front end.
Visitors whose IP address you list in Settings > SEO Debug Bar. Behind a proxy or a CDN the server sees the proxy’s address, which is why administrators do not need it.
Nobody else: for any other visitor the plugin loads no script, no style and no panel.

Privacy

The audit runs in your browser, on your own site. The plugin makes no request to any other server: the only extra requests are to your own site, for robots.txt, the sitemap and the favicon. It sets no cookie and collects no data.

Developed by a WordPress developer in Montreal.