JSON validation final check: syntax is only the first layer

A JSON Validator can confirm that the document parses, but a valid document may still violate the application's schema. After syntax validation, check required keys, types, allowed values, duplicate-key policy, and representative nested records. Watch for strings where numbers are expected and nulls where values are required. If the data contains dates or URLs, validate their intended semantics separately. A green syntax result should not be presented as proof that the receiving system will accept the payload.