Checks that measure what your website actually does right now: SSL validity and expiry, response headers, redirect chains, robots.txt and sitemap correctness, social share tags, and the Website Health Checker, which composes nine real probes into one scored report.
Every result is a live measurement made at the moment you ask, never a cached or invented number, and every failing check links to the specific tool that diagnoses it deeper.
Every check here is made from the outside, which is the point and also the limit. These tools see exactly what a visitor's browser sees, with no access to your server, your logs or your code, so a finding is something anybody can observe about your site, including a customer or a competitor. What they cannot do is crawl your whole site or explain why a server behaves the way it does: they measure one URL at a time, and the reason usually sits in a configuration file only you can read.