What structured data is for
Structured data describes a page in a vocabulary search engines share (schema.org): this is a product with this price, this is an article by this author, these are questions and answers. It makes a page eligible for rich results and helps AI assistants understand it.
JSON-LD in a script tag is the format Google recommends. This checker parses every block, lists the types it finds, and checks the fields Google's rich results most often need.
Questions
Is this the same as Google's Rich Results Test?
It covers the common checks quickly. Use Google's test for the final word on rich result eligibility.
Does schema improve rankings?
Not directly; it can earn rich results, which improve clicks.
Which format should I use?
JSON-LD. It is easiest to maintain and Google's preferred format.
Why is my JSON invalid?
Often a trailing comma, an unescaped quote, or two objects without an array. The error shows where parsing failed.