Heading Structure Checker

Heading levels can look completely fine visually while being broken underneath — a theme's default styling might make an H4 look identical to an H2, so a skipped level (H2 straight to H4, with no H3) is invisible to the eye but still readable by a search engine's crawler or a screen reader that relies on the actual heading hierarchy to navigate the page.

More than one H1 causes a similar problem: it leaves ambiguity about which heading is actually the page's main topic, which is exactly the kind of structural detail a crawler picks up on even when no human reader would ever notice it.