Alex

Simple on-page SEO Checker, based on on React, Redux and Chai
You can use custom tests, more information here: <a href="https://github.com/seo-checker/seo-cheker" rel="nofollow ugc">SEO checker</a>

Luway SEO Checker

hitmax1978

Find the post. Click “Edit post”. Activate the “Text” tab of your post.
To modify the title tag of your post, add a simple string into your post content: 
<!—title=”your title”—> (See screenshot-1)
To modify the description tag of your post, add: 
<!—description=”your description”—> (See screenshot-1)
IMPORTANT!!! Be sure after “<!” characters you have two “-” characters. It is similar to HTML comment tag.
Multilingual support
If some kind of multilingual plugins are active (for example Multilanguage by BestWebSoft) – you can define titles and descriptions in other way: (See screenshot-2)
English locale (United States) 
<!—title_en_US=”your title”—> 
<!—description_en_US=”your description”—>
Українська локаль 
<!—title_uk=”Ваш заголовок”—> 
<!—description_uk=”Ваш опис”—>
Русская локаль 
<!—title_ru_RU=»Ваш заголовок»—> 
<!—description_ru_RU=»Ваше описание»—>
Feedbacks are welcome. Visit <a href="http://onlineservicetools.com/meta-tags-from-content-wp-plugin-discussion-feedbacks" rel="nofollow ugc">onlineservicetools.com</a>

MetaTagsFromContent

Good in multilingual site

Generates title and description tags from post's content.

Luway SEO Checker vs MetaTagsFromContent