The Schema Markup Validator checks Schema.org data, exposes the extracted graph and syntax issues, but cannot certify search-result eligibility.
Scope and boundary
The Schema Markup Validator checks Schema.org-based structured data and exposes the extracted graph and syntax issues; it does not certify search-result eligibility.
Practical workflow
Validate syntax and graph structure, then compare every entity and value with rendered facts. Test live output where scripts or widgets may change the graph. I validate visible facts before fixing a checker message; that is a method, not a rich-result guarantee.
Apply Schema Markup Validator to a concrete condition
Validator work is controlled by the facts exposed on the page and the graph those facts create. For example, when a page declares a product price or availability, compare the visible selection state, currency and availability text with the JSON-LD entity before correcting a warning. Test the live URL as well as pasted code when a widget or client-side script can add a second graph. A clean Schema.org parse cannot tell whether the values are truthful, current or eligible for a Google feature.
What to verify
For a verification example, a validator may reveal two Product entities where a page should present one selected offer. Do not remove an entity blindly: first identify whether it comes from a theme, a review widget or a separate visible offer, then align or remove the inaccurate source. Re-run the live URL after the smallest correction and compare with the rendered content. The goal is a truthful understandable graph, not an empty warning list.
Common mistakes
Avoid treating Schema.org validation as a ranking checker or a substitute for accurate content.