Quick answer
Make the JSON-LD payload valid JSON first, then validate whether its schema and properties suit the page. Syntax validity is necessary but does not guarantee eligibility for enhanced search features.
What the issue means
JSON-LD is a JSON object placed in a <script type="application/ld+json"> element. Invalid quotes, trailing commas, unescaped characters, template output, or incomplete variables can make the payload impossible to parse.
Why it matters for SEO
Invalid structured data cannot be reliably consumed as structured data. Fixing syntax does not guarantee rich results, rankings, or traffic; eligibility also depends on the content, feature requirements, and search-engine policies.
How NOTABIS detects it
The invalid-jsonld rule is page-scoped and medium severity when structured data is not valid JSON. The rule checks JSON validity; it is not a complete schema eligibility review.
How to check it yourself
View the delivered HTML, copy each JSON-LD script payload, and parse it with a JSON parser. Also inspect the browser console and a current structured-data testing tool. Test the rendered response, not only the template source.
How to fix it
Generate JSON with a proper encoder rather than string concatenation. Escape dynamic values, remove trailing commas, emit valid UTF-8, and ensure optional fields are omitted or encoded correctly. Revalidate after deployment and confirm the structured data describes visible page content.
When it may be intentional
A page may have no structured data at all; that is different from emitting invalid JSON-LD. Optional or experimental markup should not be retained in a broken state merely to satisfy a catalogue check.
Related issues
Review valid JSON-LD, microdata, RDFa, and page content separately.
Run a NOTABIS audit
NOTABIS identifies pages where the delivered JSON-LD cannot be parsed, allowing you to trace the problem to its template or data source.