Ask HN: Any SEO article checker tool to recommend?

I've been doing some blog posts for jobboardsearch.com and would be handy a SEO checker tool, like:

- Teat metas - Test H tags - Teat content based on keyword - Teat density - etc. etc.

I've googled and found a few but nothing that I liked thus the question.

Can you suggest an article SEO check tool?

Thanks :)