Schema Markup Checker: 3 Free Ways to Check Your Structured Data

What does a schema markup checker actually check?

A schema markup checker finds the structured data in a page's code and lists the types it found, plus any errors. Structured data is, in Google's definition, "a standardized format for providing information about a page and classifying the page content." On most business sites it sits in a JSON-LD script block that visitors never see.

Checkers differ in what they test the markup against. Google's tool asks whether the markup qualifies for a Google rich result. The schema.org validator asks whether the markup follows the schema.org vocabulary. Our check asks whether the markup names the business behind the site. Google's structured data guide says Google uses the markup it finds "to understand the content of the page," and gathers facts from it about "the people, books, or companies that are included in the markup."

Which schema checker should you use: Rich Results Test, Schema Markup Validator or our free check?

Each of the three tools answers a different question, so most sites need more than one. The Rich Results Test reports which rich result types it found and any errors. Since 2021 the Schema Markup Validator has checked "syntax and compliance of markup with schema.org standards" and, in Google's December 2020 announcement, "will no longer check for Google Search rich result types."

Does AI use schema markup?

Google and Microsoft both say structured data helps their systems understand a page, and Google says no special schema is needed for its AI features. Google's page on AI features and your website, updated December 10, 2025, says "there's also no special schema.org structured data that you need to add" and that "there are no additional requirements to appear in AI Overviews or AI Mode." A page has to be indexed and eligible to show in Search with a snippet. Google's AI optimization guide, updated July 10, 2026, says structured data "isn't required for generative AI search" and is still worth using because "it helps with being eligible for rich results on Google Search."

Microsoft puts more weight on it. In an October 8, 2025 post, Krishna Madhavan, a principal product manager at Microsoft Bing, wrote that schema "is a type of code that helps search engines and AI systems understand your content" and listed it among his core practices for AI search visibility. Neither company says markup gets a page cited by an AI engine, and we don't claim it either.

Where the markup lives also matters. Google can read JSON-LD that JavaScript adds after the page loads, including markup added through Google Tag Manager. In Vercel's December 2024 crawler study, the OpenAI crawlers it measured (GPTBot, OAI-SearchBot and ChatGPT-User), Anthropic's ClaudeBot and PerplexityBot did not run JavaScript. Gemini, which uses Googlebot's infrastructure, and AppleBot did. That study covered 569 million GPTBot requests in one month, and crawlers change, but markup in the HTML your server sends reaches every one of them. Our guide to showing up in ChatGPT results covers the rest of what ChatGPT reads.

Why can valid schema markup still fail to name your business?

Valid schema markup can describe only the web page and the site, with nothing that says which business runs it. SEO plugins and site builders add markup by default, and much of it describes site structure: WebSite, WebPage, BreadcrumbList, ImageObject. Those types pass every validator because they are valid schema.org, but none of them describes the business.

The clearest case is a small fragment called PropertyValueSpecification. Yoast SEO's developer documentation describes a SearchAction it adds to the WebSite node when a site supports internal search, and that SearchAction carries a query-input property of type PropertyValueSpecification. The markup exists for Google's sitelinks search box, which Google stopped showing on November 21, 2024. Google said the leftover markup "won't cause issues in Search" and that there is no need to remove it. It is harmless, and it says nothing about who you are.

Markup that does name you is an entity node: an Organization or LocalBusiness with your name, address and contact details. Google's Organization documentation, updated September 8, 2026, says adding it to your home page "can help Google better understand your organization's administrative details and disambiguate your organization in search results." Google's LocalBusiness documentation has two required properties: name and address.

How does the free AI visibility check decide if your schema passes?

The free AI visibility check passes your structured data only when your homepage markup has a named business entity at the top level. Top level means the node stands on its own in a JSON-LD block or is a direct member of its @graph list. The types that count are Organization and LocalBusiness with all their schema.org subtypes, Product, Service, SoftwareApplication, and a Person who is the subject of the page. A Person who appears only as an article's author does not count, because a byline names a writer.

Nested fragments never count. An Organization tucked inside a WebSite node's publisher property is part of the WebSite description, so it does not pass on its own. Plugin boilerplate never counts either: WebSite, WebPage, BreadcrumbList, SearchAction, ReadAction, EntryPoint, ImageObject and PropertyValueSpecification can all be valid and still fail this check.

Subtypes matter for local businesses. Schema.org lists 30 more specific types under LocalBusiness, from Dentist to Store, and HomeAndConstructionBusiness alone has 8, including Plumber, Electrician and HVACBusiness. A plumber marked up as Plumber passes the same way as one marked up as LocalBusiness.

Structured data is one of five things the check looks at on your homepage. The score counts three of them: AI crawler access in robots.txt, structured data, and page weight and load time. llms.txt and platform are shown for information and never count. The check does not read every page, so a pass tells you about your homepage only. You get the full report on every check, emailed.

How do you check schema markup step by step?

Check schema markup with Google's tool, the schema.org validator, a read of the types found and the free check, then fix what they flag.

• Run your homepage URL through the Rich Results Test. Per Google's help page it accepts a URL or pasted code and reads JSON-LD, RDFa and Microdata.
• Run the same page through the Schema Markup Validator to catch schema.org errors in types Google does not use for rich results.
• Read the list of types each tool found. If it shows only WebSite, WebPage, BreadcrumbList and similar types, nothing on the page names your business.
• Run the free AI visibility check to see whether your homepage names a business entity, next to crawler access and page weight.
• Fix the critical errors the Rich Results Test flags first. Google's LocalBusiness guide says to fix any critical errors, and that fixing non-critical issues "isn't necessary to be eligible for rich results." Separately, Google's structured data guidelines say Google "does not guarantee that your structured data will show up in search results," even when the test shows the markup is correct.

What happened to Google's Structured Data Testing Tool?

Google's Structured Data Testing Tool was split in two: the Rich Results Test stayed at Google and the Schema Markup Validator moved to schema.org. On December 15, 2020, Google announced it would migrate the old tool "to a new domain serving the schema.org community by April 2021." Schema.org announced the Schema Markup Validator as its new home on May 11, 2021. On August 9, 2021 Google began redirecting the old tool to a landing page that helps you pick the right one.

What is the difference between schema and structured data?

Structured data is the general practice of labelling page content for machines, and schema.org is the shared vocabulary most of that labelling uses. Schema.org is a collaborative project whose founding companies are Google, Microsoft, Yahoo and Yandex. It defines types and properties such as LocalBusiness, address and telephone.

The format is a separate choice. Google supports JSON-LD, Microdata and RDFa and recommends JSON-LD, a script block that is "not interleaved with the user-visible text." When people say schema markup, they usually mean schema.org types written as JSON-LD.

How do you add schema markup to your site?

Add schema markup as a JSON-LD script in your page's HTML, either by hand or through your CMS's SEO plugin. Google's LocalBusiness guide sets out the order: add the required properties, insert the markup, use a CMS plugin if that is easier, validate with the Rich Results Test, then deploy a few pages and use the URL Inspection tool to test how Google sees them.

Two of Google's structured data guidelines apply to every type: "Don't mark up content that is not visible to readers of the page," and the markup "must be a true representation of the page content." If your homepage says you serve Ottawa, the markup should say Ottawa too. If a plugin writes your markup, run the result through a checker and look for your business name among the types it lists. An llms.txt file does a different job: it points AI tools at your best pages, while markup labels what a page is about.

Frequently asked questions

What is the best free schema markup checker? Use Google's Rich Results Test for Google features and the Schema Markup Validator at validator.schema.org for schema.org correctness. Both are free. Neither tells you whether the markup names your business, which is what the free AI visibility check tests on your homepage, alongside AI crawler access and page weight.

Is the Schema Markup Validator the same as the Rich Results Test? No. The Schema Markup Validator checks markup against the schema.org vocabulary and has not checked Google rich result types since Google moved it to schema.org in 2021. The Rich Results Test checks the rich result types Google supports and reports which ones it found, plus any errors.

Does schema markup help you appear in AI Overviews? Google says no special schema.org markup is needed to appear in AI Overviews or AI Mode, and a page only has to be indexed and eligible to show in Search with a snippet. Google still recommends structured data because it helps with rich result eligibility and helps Google understand the page.

Can AI crawlers read schema added by JavaScript? Google can read JSON-LD that JavaScript adds. Vercel's December 2024 study found that the OpenAI, Anthropic and Perplexity crawlers it measured did not run JavaScript, so markup added by a script would not reach them. Gemini and AppleBot did render JavaScript. JSON-LD in the HTML your server sends works for all of them.

Should I remove old sitelinks search box markup? You don't have to. Google stopped showing the sitelinks search box on November 21, 2024 and said leftover markup won't cause issues in Search or errors in Search Console. That markup does not identify your business, so it should not be the only structured data on your homepage.