JSON-LD Validator

What this tool does

The JSON-LD Validator checks structured-data markup for problems before you publish it. Paste either a raw JSON-LD object or a full <script type="application/ld+json"> block — the script tags are stripped automatically — and the tool parses it and reports back. It separates findings into three clear groups: errors that will stop the markup working, warnings about weak or incomplete markup, and passed checks that confirm what is correct. It also lists every @type it detects anywhere in the document, including nested objects and items inside an @graph array, and shows a clean, pretty-printed copy of valid input.

It is a structural validator, not a crawler. It does not fetch your page, follow links, or contact any external service. Every check runs locally in your browser.

Why it matters for SEO

Structured data only earns rich results if search engines can read it without tripping over a mistake. A single misplaced comma makes the entire JSON-LD block invalid, and Google will silently ignore it — no error in your face, just no rich result. A missing @type leaves an item undefined. A missing recommended property, such as a headline on an Article or mainEntity on an FAQPage, can quietly disqualify a page from the enhanced listing you were aiming for.

Catching these problems early saves real time. Editing JSON-LD, redeploying, waiting for a recrawl and only then discovering a syntax error is a slow loop. A quick offline check on the draft markup closes that loop in seconds. It is especially useful when markup is generated by a CMS or a template, where a stray variable can break the JSON for an entire content type at once.

JSON-LD is the format Google recommends precisely because it is self-contained and easy to validate — unlike microdata, which scatters attributes through your HTML and cannot be checked as one isolated block. This tool leans on that advantage: one block in, a full structural report out.

How to use it

1. Copy your structured data — either the raw JSON or the entire <script> block from your page source.
2. Paste it into the input box. Load the sample first if you want to see a working example.
3. Read the report. Errors appear in red, warnings in amber, and passed checks in green, with a count summary at the top.
4. Review the detected @type list to confirm the document describes what you expect.
5. Fix any errors, address the warnings that matter, then copy the formatted output if you want the tidied version.
6. Finish by running the live URL through Google’s Rich Results Test.

SEO best practices

Always declare "@context": "https://schema.org" at the top level so terms resolve correctly. Give every item a @type. Include the recommended properties for your type — they are recommended because they are what rich results are built from. Keep the markup matched to the visible content on the page. When you use an @graph array to describe several connected entities, check that each node inside it is itself complete. Validate after every change to a template that emits structured data, not just once.

Common mistakes to avoid

The classic mistake is trusting “the JSON is valid” as the finish line — valid syntax is necessary but not sufficient. Watch for trailing commas and unescaped quotes, the two most common parse failures. Do not omit @context or @type; both are foundational. Avoid marking up content that is not visible on the page. And do not treat this validator as the final word: it is an offline structural check, not Google’s rendering pipeline. It cannot tell you whether a page will actually show a rich result — only the Google Rich Results Test, running against your live URL, can do that.

Privacy & your data

The JSON-LD Validator is fully client-side. The markup you paste is parsed and analysed by JavaScript running in your own browser. Nothing is uploaded, nothing is logged, and nothing is stored once you close or refresh the page. There is no server round trip at any point — that is also why the tool cannot contact Google on your behalf. Because your data never leaves your device, you can safely validate structured data for staging environments, unreleased products and internal pages. You stay in control of when, and whether, that markup ever goes public.