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SEO and auditingChecked through WebDiag API

Structured Data Validator

Enter a URL to inspect JSON-LD blocks on a page: how many were found, which Schema.org types are declared, whether syntax errors exist, and what to fix before rich-result tests.

  • JSON-LD
  • Schema.org types
  • Parse errors
Online tool

Try the tool

Enter a URL: WebDiag will run a safe network check and show the result.

Page URL

Structured data

After the check, JSON-LD blocks, validity, Schema.org types, and parse errors will appear here.

Network check through backend

For HTTP/SEO tools, the URL is sent to the WebDiag API, where SSRF protection, DNS/IP policy, and redirect limits are applied.

Reviewed: 2026-07-17
01

How to use it

  1. 1

    Paste the page URL that contains structured data.

  2. 2

    Run the check through the WebDiag API.

  3. 3

    Review JSON-LD validity, detected types, and errors for each block.

02

What the tool can do

  • Extracts all script type=application/ld+json blocks from the page HTML.
  • Shows valid and invalid blocks, Schema.org types, and JSON-LD node counts.
  • Uses SafeHttpFetcher with SSRF protection and HTML body size limits.
03

Common use cases

  • Find broken JSON-LD after CMS template changes.
  • Check which Schema.org types are actually delivered in HTML.
  • Prepare a page for later verification in Google rich results tools.
04

How it works inside

The check performs syntactic JSON parsing and recursively collects @type values.

This is not an external Google Rich Results Test integration and not a Schema.org reasoner.

05

Questions and answers

Why does it not promise rich snippets?

Because eligibility depends on data type, page content, search engine policy, and markup quality. WebDiag honestly reports JSON-LD validity and types.

Can it check multiple JSON-LD blocks?

Yes. The tool shows every block separately and summarizes detected types.