Schema.org Validator

Validates structured data markup (JSON-LD, Microdata, RDFa) using Google's validator.schema.org API.

When to Use

digraph when_to_use {
    "User asks about schema validation?" [shape=diamond];
    "URL or HTML file provided?" [shape=diamond];
    "validate-schema" [shape=box style=filled fillcolor=lightgreen];
    "Ask for URL or file" [shape=box];
    "Use other skill" [shape=box];

    "User asks about schema validation?" -> "URL or HTML file provided?" [label="yes\n(schema.org, JSON-LD,\nstructured data, SEO)"];
    "User asks about schema validation?" -> "Use other skill" [label="no"];
    "URL or HTML file provided?" -> "validate-schema" [label="yes"];
    "URL or HTML file provided?" -> "Ask for URL or file" [label="no"];
}

Use this skill when:

• User asks to validate schema.org markup
• User wants to check JSON-LD structured data
• User asks about structured data errors or warnings
• User wants to verify SEO structured data implementation

Instructions

1. Determine Input Type

For live public URLs:

curl -s -X POST 'https://validator.schema.org/validate?url=[URL]&output=json' | tail -c +5 | jq

For local HTML files (static, no JS rendering needed):

curl -s -X POST 'https://validator.schema.org/validate?output=json' --data-urlencode "html@[filepath]" | tail -c +5 | jq

For localhost/dev servers (static HTML only): Pipe HTML directly to the validator:

curl -s "http://localhost:3000/page" | curl -s -X POST 'https://validator.schema.org/validate?output=json' --data-urlencode "html@-" | tail -c +5 | jq

For localhost/dev servers with JavaScript-rendered content (RECOMMENDED for SPAs and dynamic sites):

Use Chrome headless to render the page fully, then pipe directly to the validator:

/Applications/Google\ Chrome.app/Contents/MacOS/Google\ Chrome \
  --headless --dump-dom "http://127.0.0.1:5500/page" 2>/dev/null | \
  curl -s -X POST 'https://validator.schema.org/validate?output=json' \
  --data-urlencode "html@-" | tail -c +5 | jq

This executes JavaScript and captures the fully-rendered DOM, ensuring all dynamically-generated schema.org markup is included in the validation. The @- tells curl to read from stdin, avoiding temp files.

Note: If Chrome is not at the default macOS path, check common locations:

• macOS: /Applications/Google Chrome.app/Contents/MacOS/Google Chrome
• Linux: google-chrome or chromium-browser
• Windows: C:\Program Files\Google\Chrome\Application\chrome.exe

2. Parse Response

Key response fields:

• totalNumErrors: Number of validation errors
• totalNumWarnings: Number of warnings
• numObjects: Count of schema.org entities found
• tripleGroups: Detailed breakdown of each entity
• errors: Array of error messages

3. Format Results

Present the results in a clear, structured format:

# Schema.org Validation Report: [URL/File]

## Summary
- **Status**: [VALID / HAS ERRORS / HAS WARNINGS / NO SCHEMA FOUND]
- **Entities Found**: [numObjects]
- **Errors**: [totalNumErrors]
- **Warnings**: [totalNumWarnings]

## Entities Detected

| Type | Properties | Errors | Warnings |
|------|------------|--------|----------|
| [Type] | [property list] | [count] | [count] |

## Issues Found

### Errors
- [List each error with context]

### Warnings
- [List each warning with context]

## Recommendations
[Provide actionable fixes for any issues found]

4. Error Handling

If validation fails:

• Check if URL is accessible
• For local files, verify file exists and contains HTML
• Note that validator.schema.org is undocumented and may rate-limit

Example Usage

User: "Validate the schema.org markup on https://example.com" User: "Check the JSON-LD in my local index.html" User: "Does my localhost site have valid structured data?"

Tips

• The )]}' prefix (4 bytes) in responses is an anti-JSON hijack measure; strip with tail -c +5
• Use jq for readable JSON output
• For sites without schema.org markup, numObjects will be 0
• Check tripleGroups[].nodes[].errors for per-entity issues
• Nested entities (like Review inside Product) appear in nodeProperties