JSON-LD Validator

A JSON-LD Validator focuses on the JSON layer of linked data. It answers a foundational question: can the structured data be parsed consistently as JSON, and does the object expose expected linked-data keys such as `@context` and `@type`? This is useful before debugging higher-level Schema.org semantics.

JSON-LD is often generated dynamically from CMS fields, TypeScript objects or template variables. A missing quote, unescaped line break or undefined value can break the entire block. Because users never see the script content directly, these failures can survive for weeks unless validation is part of QA.

1. 1Paste only the JSON-LD payload or a clean JSON object.
2. 2Run validation and fix parsing errors at the exact character or line reported by the browser parser.
3. 3Confirm `@context` and `@type` are present where your implementation requires them.
4. 4Inspect nested arrays and objects for accidental strings or null placeholders.
5. 5Retest the final rendered JSON-LD from production, not only the source object in your codebase.

• Valid JSON means braces, arrays, strings, commas and values follow JSON syntax.
• A parsed object can still contain wrong Schema.org properties.
• Arrays are valid JSON-LD containers when multiple entities are intentionally represented.
• The safest troubleshooting order is JSON syntax first, linked-data structure second, rich-result rules last.

• Using single quotes instead of JSON double quotes.
• Leaving comments inside JSON.
• Trailing commas after the final property.
• Serializing HTML entities or escaped strings incorrectly.
• Passing a JavaScript `undefined` value into output that expects strict JSON.

• Serialize structured data with `JSON.stringify` or an equivalent safe serializer instead of hand-concatenating strings.
• Escape user-entered text before it reaches a script context.
• Remove comments and JavaScript-only syntax.
• Use automated tests that parse generated JSON-LD during builds.

• Keep structured-data generation close to the real content model.
• Do not duplicate business facts in several places unless the same source of truth feeds them.
• Review rendered output after framework upgrades.
• Validate representative templates, including pages with optional fields missing.

The validator cannot determine whether every Schema.org property is appropriate for your business or whether a search engine considers the page eligible for a feature.