How Do You Test Schema Markup and Fix Structured Data Errors?

By Bill Stilwell · Last reviewed October 16, 2026

The short answer

Test every page with structured data in two free tools before and after you publish. Google’s Rich Results Test shows which Google rich results the page can get. The Schema Markup Validator checks that the code follows the general schema.org rules. After launch, check the rich result reports in Google Search Console, fix any problems in your site’s code, and ask Google to check again.

What this means

Structured data is code that labels facts on a page, like your business name, phone number, a product price, or an event date. Mistakes in that code are easy to make and hard to see. Testing catches them.

There are three tools, and each does a different job:

Rich Results Test (Google). Shows which Google rich results your page can produce and can preview how they may look. Google suggests starting here.
Schema Markup Validator. Checks any schema.org markup, not just the types Google uses. It doesn’t apply Google’s own rules, so use it alongside the Rich Results Test, not instead of it.
Search Console rich result reports. Show the structured data Google actually found on your live site. Google gives a separate report for each rich result type it found. A report only shows up if Google found that type on your site and has a report for it.

Say Clearwater Pool Service adds local business markup to its home page. The Rich Results Test passes. A month later, a new plugin adds a second, broken block of markup. Nobody notices until someone checks the Search Console report and sees invalid items.

Why it matters

Broken markup does nothing. Google says an invalid item has at least one critical issue that keeps it from appearing as a rich result.
Wrong markup can mislead. Code that says something different from the page breaks Google’s rules and confuses search engines and artificial intelligence (AI) tools that read it.
Sites change. Theme updates, new plugins, and page edits can break markup that used to work.

Who this applies to

Anyone with structured data on their site. That includes markup your website builder or plugins add without asking you.

You can skip this only if your site has no structured data at all. Even then, run one test to confirm it.

How to do it

Before you publish:

Paste the page address or the code into the Rich Results Test.
Read the results. Note which rich result types it found and any issues listed.
Run the same page through the Schema Markup Validator to catch general schema.org problems.
Compare what the tools found with what the page shows. The name, address, phone, prices, and dates in the code must match the visible page.
Fix the code and test again until the issues are gone.

After you publish:

Open Google Search Console and look for the rich result reports for your site (see 13.8 Website Launch Checklist if Search Console isn’t set up).
Look at invalid items first. Google calls these critical issues. They stop the item from showing as a rich result.
Look at the non-critical issues next. Google lists these as ways to improve how the item looks. They don’t make the item invalid.
Fix problems in your site’s code. Search Console doesn’t fix them for you.
Use the validation option in the report so Google rechecks the pages. The report shows the validation status once you start it.
Retest after any theme change, plugin change, or big content edit.
Add a structured data check to your regular content reviews (see 19.12 Content Maintenance).

Google says passing the test doesn’t guarantee your rich result will show. Google decides what to show for each search.

What proof to keep

Rich Results Test and Schema Markup Validator screenshots for your key pages, with dates
Screenshots of Search Console rich result reports
A short log of each error, the fix, and the date validation passed

Keep these in your website records folder.

Common mistakes

Testing only once. Markup breaks when sites change. Test after every update.
Only using the Schema Markup Validator. It doesn’t check Google’s own requirements.
Ignoring markup added by plugins. Two plugins can each add markup for the same business, with different details.
Thinking “valid” means “will show.” Valid markup makes a page eligible. It doesn’t guarantee a rich result.
Fixing the warning, missing the error. Critical issues come first.
Expecting reports to show every item. Google says the reports show a sample, so totals may be lower than the real count.

When to get help from a pro

Your web developer or search engine optimization (SEO) specialist: if errors keep coming back or you can’t tell where the markup comes from. Questions to ask:

Where does each block of structured data on our site come from, the theme, a plugin, or custom code?
Can you remove duplicate markup so only one accurate version remains?

Bill’s note

[Bill: add a short story or lesson here. For example, a site where a plugin update broke the markup without anyone noticing, or how often you check structured data for clients.]

If you’d rather have this done for you, SiteSmarty can test and monitor structured data on websites it manages.

How I did this for SiteSmarty

[Date I did this:]
[What I actually did, step by step: which SiteSmarty pages I tested and what the tools found]
[What it cost and how long it took:]
[What surprised me or what I’d do differently:]
[Screenshot or photo to add, with private info blurred: Rich Results Test and Schema Markup Validator results for the SiteSmarty home page]
[Result so far:]

Questions people ask

What’s the difference between the two testing tools? The Rich Results Test checks for Google rich results. The Schema Markup Validator checks general schema.org rules. Use both.

What does an invalid item in Search Console mean? Google says it has at least one critical issue that keeps it from appearing as a rich result.

My markup passes the test, so why don’t I see rich results? Google doesn’t guarantee rich results. Passing makes the page eligible, nothing more.

How do I tell Google I fixed an error? Fix the code on your site, then use the validation option in the Search Console report.

How often should I check? After every site change, and as part of your regular content review.

Audit check

Question: Do all key pages pass the Rich Results Test, with no invalid items in Search Console?
Pass looks like: Dated passing results for the home page and other marked-up pages, no critical issues in Search Console, and markup that matches the visible page.
Fail looks like: No testing records, invalid items left unfixed, duplicate markup from plugins, or markup that disagrees with the page.
Evidence to collect: Test screenshots, Search Console rich result report screenshots, and the error fix log.

Where this fits

Do this first: 19.6.1 Local Business Structured Data

Do this next: 19.7 Entity Consistency

Sources

Google Search Central, "Test your structured data" (checked October 16, 2026)
Search Console Help, "Rich result reports" (checked October 16, 2026)
Google Search Central, "Event (Event) structured data" (note that structured data isn't guaranteed to show) (checked October 16, 2026)

This page explains general rules and Bill's own experience. It is not legal, tax, or insurance advice. Talk to a qualified professional about your situation.