Free tool · no signup
Free schema markup generator and checker
See what structured data you already have, and what is missing.
Structured data is how you tell a search engine what a page is rather than leaving it to guess — a product, an article, an organisation, a set of questions. It is also where a lot of sites quietly fail: invalid JSON-LD is skipped silently, so a page can look marked up and count for nothing.
This checks what is on your page now, flags blocks that will not parse, and generates the Organization and WebSite markup most sites are missing.
What this free version does not do
It generates the site-level markup that can be derived from a page you already have. Article, Product and FAQ markup depend on the content of each individual page, which is something Xeostack writes per page rather than something a single URL can tell you.
Other free tools
These are one page each. Xeostack does the same work across your whole site, continuously.