Ask HN: Any SEO article checker tool to recommend?

Hi there, 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 :)