Free schema markup validator: valid is not the same as correct
Most structured data problems are not syntax errors. They are markup that parses perfectly and describes a page that does not exist.
By Sapun Lamichhane · Arcetis
Structured data fails in two ways that look nothing alike. One is a syntax error, which every validator catches. The other is markup that parses flawlessly and describes a page that does not exist — and almost nothing catches that except a human reading both.
The failure that gets sites penalised
Search engine guidelines are explicit: structured data must describe content visible on the page. Marking up a rating nobody can see, a price that is not shown, or an author who appears nowhere is a violation, and it is grounds for a manual action that removes your rich results entirely.
This is rarely deliberate. It happens when a template outlives the content it was written for — the product page stops showing reviews, and the aggregateRating block stays behind because nothing connected the two.
Why type names should not be string-matched
JSON-LD allows the same entity to be expressed several ways. A page may declare a custom @context, alias a term, or use a vocabulary prefix, and all of these are correct. A validator that matches the literal string "Organization" will report a perfectly good Organization entity as missing.
Expanding the document first — resolving every term against its @context to a full schema.org IRI — is the difference between checking what a page means and checking how it happens to be spelled.
One accurate type beats five speculative ones
There is a persistent belief that more types means more coverage. It does not. Speculative types risk contradicting each other, and a page carrying Article, NewsArticle and BlogPosting simultaneously has told a search engine three things about itself, at least two of which are guesses.
Pick the type that genuinely describes the page. Add Organization and WebSite site-wide, BreadcrumbList wherever there is a hierarchy, and FAQPage or HowTo only where the content actually takes that shape.
Why this matters more for AI than for search
For search, structured data is an enhancement — it changes how a result is displayed. For an assistant, it is the difference between a fact and an inference. A price in prose has to be interpreted; a price in an Offer is stated. That distinction decides how confidently a model repeats it, and how likely it is to repeat it wrongly.
What free means here
Our structured data checker is free, with no account needed for your first scan. It expands your JSON-LD properly, reports the entity types and properties it finds, and treats absence as detection rather than failure — a law firm is not defective for lacking Recipe markup, and an audit that says otherwise is wasting your attention.