1. Trailing commas
Strict JSON does not allow a comma after the last object or array item.
{ "@type": "Product", "name": "Keyboard", }Remove the comma after "Keyboard". Our preview auto-fix can remove straightforward trailing commas.
2. Smart quotes are not JSON quotes
Text editors sometimes turn straight " marks into curved quotation marks. JSON property names and string delimiters must use straight double quotes.
3. Missing Google fields
A schema can be valid JSON and still miss a property Google needs for a certain feature. For example, Product snippets need a qualifying offer, review or aggregate rating. Google may apply additional nested requirements.
4. @id references
When linking nodes in @graph, check that the referenced identifier points to the intended object. A local checker can only flag possible unresolved identifiers; another page may legitimately define them.
5. Dates and enums
Prefer ISO 8601 dates such as 2026-10-31 and complete Schema.org enum URLs like https://schema.org/InStock. Always review suggested edits before copying them.
Try the checker with the built-in broken example.
Frequently asked questions
Answers are educational. FAQ markup does not guarantee Google FAQ rich results.
Is valid JSON automatically valid structured data?
No. JSON syntax, Schema.org vocabulary and Google feature requirements are different checks.
Should I automatically fix missing prices or reviews?
No. Only add real, verifiable values from the page or business.
