Schema Markup Validator

What is schema markup?

Schema markup is structured data: a standard vocabulary from schema.org that describes what a page is about in a form machines can read – a product with its price and availability, an article with its author and date, a business with its address and opening hours. Search engines use it to understand the page and, for some types, to show rich results: review stars, prices, breadcrumbs, event dates or recipe details directly in the search results.

The markup is invisible to visitors. It is usually added as a JSON-LD block inside a <script type="application/ld+json"> tag in the page's HTML. Because nobody sees it, mistakes go unnoticed for months: a typo in a property name, a missing required field or a date in the wrong format quietly disables the rich result. A schema markup validator finds these mistakes before Google does.

JSON-LD vs Microdata vs RDFa

JSON-LD is a separate block of JSON inside a script tag; Microdata and RDFa are attributes (itemscope, itemprop; typeof, property) added to the visible HTML elements. All three can express the same schema.org data, and Google reads all three.

Google recommends JSON-LD: it is easier to add and maintain, it can be generated by a CMS or tag manager without touching the templates, and it does not break when the HTML layout changes. Microdata ties the data to the page structure, which makes it fragile and hard to review. This schema validator checks JSON-LD only. If a page also contains Microdata or RDFa, the tool tells you so, but does not validate those parts.

Common structured data errors and how to fix them

Most structured data errors fall into six groups. The validator explains each one and, where possible, fixes it in the corrected JSON-LD.

1. Invalid JSON. A trailing comma, single or curly quotes, a missing bracket or an unescaped line break make the whole block unreadable – search engines then ignore it completely. Fix: copy the corrected JSON-LD, which repairs the syntax and shows the line of every problem.
2. Misspelled property or type names. datePublised, Artcle or Reviews do not exist in schema.org. Unknown names are silently ignored, so the data is lost without any error in Google's reports. Fix: use the suggested correct name.
3. Missing required properties. A Product without offers, review or aggregateRating, an Event without a physical location, a JobPosting without datePosted: Google shows no rich result. Fix: add the property; the corrected JSON-LD contains a TODO placeholder in the right place.
4. Wrong value formats. Dates like 10/25/2026 instead of 2026-10-25, prices like $19.99 instead of 19.99, "availability": "In stock" instead of https://schema.org/InStock. Fix: use ISO 8601 dates, plain numbers and the schema.org enumeration URLs.
5. Text where an object is expected. "author": "Jane Doe" should be "author": { "@type": "Person", "name": "Jane Doe" }. Google needs the object to read the name and URL.
6. Markup for retired rich results. FAQ (retired May 2026), How-to (2023) and the sitelinks search box (2024) are still valid schema.org, but Google no longer shows them. The validator says so instead of reporting them as fine.

One thing no tool can check: the structured data must describe content that is actually visible on the page. Markup for reviews, prices or events that visitors cannot see violates Google's guidelines and can lead to a manual action.

What this structured data checker tests

The validator works in three layers, from the pure syntax up to Google's rules:

1. JSON syntax. Every syntax error is reported with its line and column, in plain words, and repaired in the corrected version where that is possible.
2. Schema.org vocabulary. Every type and property is checked against the current schema.org release (the version and date are shown under each result). Unknown names get a spelling suggestion; properties that schema.org does not define for the type, outdated names, expected value types (dates, URLs, numbers, enumerations, nested objects) are all checked.
3. Google rich result requirements. For Article, Product and Offer, Review and AggregateRating, BreadcrumbList, Organization, LocalBusiness, FAQPage, Event, Recipe, VideoObject and JobPosting the tool checks the required and recommended properties from Google Search Central, plus the typical pitfalls: breadcrumb positions, ratings outside their scale, expired dates, online-only events, job postings without a country.

Errors (red) make the block unusable or block the rich result. Warnings (yellow) are recommended improvements. OK (green) lists what is already right, so you can see at a glance what Google will find.

How this differs from the Rich Results Test and validator.schema.org

Google's Rich Results Test tells you whether a live page qualifies for Google's rich results. It reports “missing field” without explaining why or how to fix it, checks Google's result types only, and needs a public URL that Googlebot can fetch. The Schema Markup Validator at validator.schema.org checks the schema.org vocabulary only: it does not know Google's requirements and reports nothing about missing properties a rich result needs.

This tool combines both views and adds what neither does: a plain-language explanation and a concrete fix for every finding, line numbers for syntax errors, spelling suggestions for typos, and a corrected JSON-LD you can copy. Pasted code is checked inside your browser and never uploaded. It also tells you honestly when a result type has been retired by Google.

Limitations: the tool reads the HTML as delivered by the server and does not execute JavaScript, so markup injected by scripts must be pasted manually. It checks JSON-LD only, and it cannot verify that the markup matches the visible content.

How to test structured data with this schema validator

1. Enter the page URL and click “Check structured data”, or switch to “Paste code” and paste a JSON-LD block or the full page source.
2. Read the summary: how many errors, warnings and OK items the page has, and which Google rich result each block is eligible for.
3. Open each block: fix the red errors first, then the yellow warnings. Every finding says what is wrong, why it matters and how to fix it.
4. Click “Copy corrected JSON-LD”, replace the TODO placeholders with your real data and publish the corrected block.
5. Check the live page again by URL, then use Google's Rich Results Test and Search Console to confirm Google sees the same result.