---
title: "Schema Checker: Validate JSON-LD Structured Data Free"
description: "Free schema checker. Read every JSON-LD block on a page, see syntax errors, schema.org types and missing properties, and learn what each result means."
url: https://seenlens.com/tools/schema-checker
last_updated: 2026-11-06
---

# Schema checker

The schema checker reads the JSON-LD structured data on a page and reports syntax errors, schema.org types and common missing properties. It fetches the page HTML once and checks every `application/ld+json` block. The result shows whether machines can read your markup. It does not decide rich result eligibility. Google's Rich Results Test decides that.

By SeenLens. Last updated: 2026-11-06

## What does the schema checker test?

Enter a page URL. The checker requests the page once as SeenLensBot (`SeenLensBot/0.1 (+https://seenlens.com/bot)`) and reads the HTML that comes back. It follows the robots.txt rules for SeenLensBot. See the [SeenLensBot page](https://seenlens.com/bot) for details.

| Test | Result |
| --- | --- |
| JSON syntax | Every `<script type="application/ld+json">` block on the page, with a parse error for each block that fails. |
| Schema.org types | All types found, including the members of an `@graph`. |
| Entity markup | Whether Organization or WebSite markup exists. |
| Missing properties | Common gaps per type. Organization: name, url, logo. Article: headline, author, datePublished. Product: name, offers. |
| Other formats | A note when the page also uses Microdata or RDFa. |

The checker reads the HTML response of one request. If a script adds the JSON-LD after the page loads, that markup is not in the response and the checker does not see it.

## How is it different from the Rich Results Test and the Schema Markup Validator?

Three tools read structured data, and each answers a different question. Google says the Schema Markup Validator does not check Google Search rich result types. For those, Google points to the Rich Results Test.

| Tool | Question it answers | Use it when |
| --- | --- | --- |
| SeenLens schema checker | Does the page have JSON-LD, does every block parse, and are common properties missing? | You want a fast check next to crawler access, content structure and the other [AI readiness checks](https://seenlens.com/tools/geo-audit). |
| [Google Rich Results Test](https://search.google.com/test/rich-results) | Can this page produce Google rich results? It takes a public URL or pasted code. | You want rich result eligibility in Google Search. Use it instead of the SeenLens checker for that question. |
| [Schema Markup Validator](https://validator.schema.org/) | Does the markup follow schema.org? Google's 2020 announcement says its main purpose is to check syntax and compliance with schema.org standards. | You use types that Google does not support for rich results, or you want a check against the full schema.org vocabulary. |

## How do I read the result?

- **Every block parses and the types match the page.** The markup is readable. Check that each type describes content that is visible on the page.
- **A block fails to parse.** A parser cannot read a block with a JSON syntax error, so the facts in it are lost. Fix the syntax first. See [JSON-LD syntax errors](https://seenlens.com/fixes/json-ld-syntax-errors).
- **No JSON-LD found.** The HTML response has no `application/ld+json` block. Check that the server sends the script in the HTML and that you entered the right URL. See [add JSON-LD](https://seenlens.com/fixes/add-json-ld).
- **No Organization or WebSite markup.** Engines cannot read who runs the site from structured data. See [add Organization schema](https://seenlens.com/fixes/add-organization-schema).
- **Missing properties.** These are hints, not errors. Add a property only when the page shows that fact. Required properties differ by rich result type, so use the Rich Results Test for Google's list.
- **Microdata or RDFa noted.** The checker found another format. Google recommends JSON-LD when your site setup allows it.

## How do I fix schema errors?

- [Add JSON-LD](https://seenlens.com/fixes/add-json-ld): add a block with types that fit the page.
- [Fix JSON-LD syntax errors](https://seenlens.com/fixes/json-ld-syntax-errors): repair commas, quotes and brackets in each failing block.
- [Add Organization schema](https://seenlens.com/fixes/add-organization-schema): state the name, URL, logo and profile links of the site owner.

After you publish the change, run the schema checker again. Then run the Rich Results Test if you want Google rich results.

## Does schema markup help my site appear in AI answers?

No study has shown that it does. Google's AI features page says there is no special schema.org structured data to add for AI Overviews and AI Mode, and no additional requirements beyond being indexed and eligible for a snippet.

Ahrefs, an SEO tool vendor, published a study on 2026-05-11. It compared 1,885 pages that added JSON-LD between August 2025 and March 2026 with 4,000 control pages that did not. Citations in Google AI Mode (+2.4%) and ChatGPT (+2.2%) did not change in a statistically significant way. Citations in Google AI Overviews fell 4.6%, but both groups were already declining. Ahrefs concluded that schema did not meaningfully raise AI citations.

Microsoft's Bing Webmaster Guidelines say structured data may support clearer grounding but does not guarantee visibility or grounding traffic. Keep structured data for rich results, accurate entity facts and machine readable pages. Do not expect it to earn AI citations by itself.

The structured data dimension is 15% of the SeenLens score. The score measures readiness. It does not measure actual AI mentions. The [free SeenLens scan](https://seenlens.com/) runs the structured data checks as part of 43 checks in five dimensions.

[Run the free SeenLens scan](https://seenlens.com/)

## Which other SeenLens tools should I use next?

- [AI crawler checker](https://seenlens.com/tools/ai-crawler-checker): see which AI crawlers your robots.txt allows.
- [llms.txt checker](https://seenlens.com/tools/llms-txt-checker): check an /llms.txt file and build one.
- [Content Signal generator](https://seenlens.com/tools/content-signal-generator): write a robots.txt block for search, AI input and training preferences.
- [GEO audit tool](https://seenlens.com/tools/geo-audit): run all checks on one page.

## Frequently asked questions

### Is the SeenLens schema checker the same as the Rich Results Test?

No. The Rich Results Test decides whether a page can produce Google rich results. The SeenLens checker reads JSON-LD and reports syntax errors, types and common missing properties. Use the Rich Results Test for rich result eligibility.

### Why does the checker find no JSON-LD when I added it?

The checker reads the HTML from one request. A script that adds JSON-LD after the page loads does not appear in that HTML. Also check that robots.txt does not block SeenLensBot and that you entered the correct URL.

### Does schema markup get my page cited by ChatGPT or Google AI Overviews?

No proven link exists. Google says no special schema.org markup is needed for its AI features, and the Ahrefs study of 2026-05-11 found no significant citation lift. Structured data still serves rich results and entity clarity.

## Sources

- [Google: Rich Results Test](https://search.google.com/test/rich-results) (tests a public page or pasted code for Google rich results, checked 2026-11-06)
- [Google Search Central: Structured data testing tool update](https://developers.google.com/search/blog/2020/12/structured-data-testing-tool-update) (Schema Markup Validator purpose and the split from the Rich Results Test, published 2020-12-15, updated 2021-08-09)
- [Google: Introduction to structured data](https://developers.google.com/search/docs/appearance/structured-data/intro-structured-data) (JSON-LD recommended, Rich Results Test for validation, checked 2026-11-06)
- [Google: General structured data guidelines](https://developers.google.com/search/docs/appearance/structured-data/sd-policies) (markup must match visible content, testing tools, checked 2026-11-06)
- [Google: AI features and your website](https://developers.google.com/search/docs/appearance/ai-features) (no special schema.org markup and no extra requirements, checked 2026-11-06)
- [Ahrefs: Does schema markup increase AI citations?](https://ahrefs.com/blog/schema-ai-citations/) (1,885 pages and 4,000 controls, published 2026-05-11, vendor study)
- [Microsoft: Bing Webmaster Guidelines](https://www.bing.com/webmasters/help/webmaster-guidelines-30fba23a) (structured data and grounding, checked 2026-11-06)
- [Schema Markup Validator](https://validator.schema.org/) (schema.org validation tool, checked 2026-11-06)