Free Schema Validator Tool Built with Cursor AI (Find SEO Schema Errors Fast)

Checking schema markup across an entire site is tedious work. You either click through Google Rich Results one URL at a time, or you dig through page source looking for JSON-LD blocks and hoping you didn't miss anything. I got tired of doing it the manual way, so I built a tool to handle it instead. Here's what it does and how it's put together.

The Problem: Auditing Schema at Scale

Structured data is easy to get wrong and easy to lose track of, especially across large sites or multiple client projects. Most tools either require a paid SaaS subscription or only let you check one page at a time. There wasn't a fast, free way to scan an entire site and get a clear picture of where schema is missing or broken.

What the Tool Does

This is a Python-based GUI tool that automates schema auditing. Instead of checking pages one by one, you can:

• Drop in a single URL to check schema on one page
• Feed it an entire sitemap to scrape and validate every page at once
• Fetch and parse HTML to extract both JSON-LD and microdata
• Flag critical schema issues using handwritten validation rules, not a wrapper around Google's API

How the Build Works

The tool fetches each page's HTML and parses it looking for structured data, whether that's JSON-LD scripts or inline microdata. Once it finds schema, it runs it through a set of validation rules built to catch the kinds of issues that actually hurt SEO, missing required fields, malformed types, and other common mistakes.

From there, flagged pages can be sent straight into Google Rich Results for a live, side-by-side test, so you're not relying solely on the local validation. You can run this against a full sitemap or a custom list of URLs, which makes it useful for spot-checking specific templates or page types without scanning an entire domain.

Results can also be exported, so you're not stuck re-running the tool every time you want to reference past findings. That makes it easier to track fixes over time or hand off a report to a client or teammate.

Why It Matters

For SEOs, developers, and agencies managing multiple sites, structured data errors are easy to miss and expensive to ignore. Schema issues can quietly affect how your pages show up in search results. Having a fast way to audit an entire site instead of spot-checking a handful of pages means fewer things slip through the cracks, and no monthly SaaS bill required.

Key Takeaways

• Automates schema audits across a single page, a full sitemap, or a custom URL list
• Extracts both JSON-LD and microdata
• Uses custom validation rules to flag real SEO issues
• Links out to Google Rich Results for quick live testing
• Exports results for tracking fixes over time
• Built for SEOs, developers, and agencies managing multiple sites

Got a tool idea or SEO workflow you wish existed? I'm always looking for the next build. Follow along for more SEO tools and web dev projects, and let me know what you'd want to see built next.