⭐ Beginner — No coding experience needed
Schema Debugger: Finding and Fixing JSON-LD Errors
Learn how to diagnose schema errors that don't show up in Google's validator, including silent type mismatches, missing required fields, and entity reference errors.
What you will learn in this guide
- The difference between syntax errors and schema errors
- How to read the error messages each tool produces
- Five errors that Google Rich Results Test won't catch
- How to debug schema that validates but doesn't produce rich results
- When to use which validator
1 Two kinds of errors
Schema errors fall into two categories that need different tools:
| Error type | What | Tool |
|---|---|---|
| Syntax errors | Invalid JSON: trailing commas, unescaped quotes, single quotes | JSON validator |
| Schema errors | Valid JSON but wrong fields, missing required, type mismatches | Google Rich Results Test + Schema Debugger |
Why a debugger:Google's Rich Results Test only checks if you're eligible for the rich results it currently supports. It misses many schema problems that affect AI engines and other consumers of structured data.
2 Errors Google doesn't catch
| Error | Example | Why it matters |
|---|---|---|
| Wrong @type for the entity | Product schema where Organization should be | AI engines get confused about what the page is |
| Missing @id on referenced entities | Author Person object without @id | Cross-page entity linking breaks |
| String where object expected | "author": "Jane" when full Person object needed | Loses authoritative signal |
| Type cast errors | price as string instead of number | Some consumers reject the whole object |
| Reciprocal links missing | Organization missing logo or sameAs | Reduces trust signal across AI engines |
3 How to debug systematically
- 1Start with JSON syntaxPaste the snippet into the JSON validator. Fix any syntax errors first. Until the JSON is valid, nothing else can be checked.
- 2Run Google Rich Results TestFix any errors and warnings Google reports. These block rich result eligibility.
- 3Run the Schema DebuggerCatches errors Google ignores: missing @id, type mismatches, incomplete entity definitions. Each issue includes a recommended fix.
- 4Test against Schema.org specFor obscure schema types, the canonical reference is Schema.org. Each type lists required and optional properties — your JSON must match.
4 Debugging "schema validates but no rich result"
The most frustrating case: Google says your schema is fine but no rich result appears in search. Common causes:
- 1Schema describes content that isn't on the pageFAQ schema with questions that don't appear visibly to users. Google detects this and silently disqualifies.
- 2Recent type penaltyGoogle has reduced eligibility for certain schemas (Recipe in some regions, HowTo on desktop). Check Search Central blog for the latest.
- 3Content quality thresholdEven with correct schema, low-quality pages don't get rich results. Improve content first.
- 4Page not yet indexedBrand new pages can take 1-7 days for rich results to appear after first index. Be patient.
Don't spam schemaAdding multiple FAQPage or HowTo schemas to a single page in hopes of getting more rich results often triggers a manual penalty. One schema per concept, matching visible content.