How To Audit Schema On An Existing Website | Lillian Purge

How To Audit Schema On An Existing Website

Auditing schema on an existing website is one of those tasks that sounds technical but in practice is mostly about clarity and accuracy. In my experience schema problems rarely come from complex code issues. They usually come from outdated markup conflicting signals or schema that no longer reflects what the website actually says.

Most websites I audit already have some form of schema in place. Sometimes it was added years ago. Sometimes it was injected via a plugin. Sometimes it was implemented through Google Tag Manager and then forgotten about. The risk is not having no schema. The risk is having the wrong schema.

In this article I want to walk through how to audit schema properly on an existing website, what to look for, how to prioritise fixes, and how to avoid making things worse while trying to improve them. This is based on real audits and clean ups rather than ideal world implementations.

Why Schema Audits Matter More Than New Schema

I often see businesses eager to add more schema types without checking what is already there. In my opinion this is backwards.

Schema works by reinforcing clarity. If the existing markup is inaccurate or conflicting, adding more only increases confusion.

Search engines do not reward volume of structured data. They reward consistency and correctness. An audit ensures schema supports the site rather than undermining it.

Step One: Identify All Existing Schema Sources

The first thing I do is establish where schema is coming from.

On most sites schema can be injected from multiple places:

The website theme or templates
SEO plugins
Schema specific plugins
Google Tag Manager
Hard coded JSON-LD blocks
JavaScript frameworks

From experience schema conflicts almost always happen when more than one source is active.

Before you assess quality you need to know every place schema is being added.

How To Check Where Schema Is Injected

Start by viewing the page source on key pages such as the homepage contact page service pages and blog posts.

Search for application/ld+json. Each instance represents a schema block.

If you see multiple blocks check whether they are different schema types or duplicates of the same thing.

Then check Google Tag Manager preview mode if GTM is installed. Look for Custom HTML tags that inject JSON-LD.

Also review your CMS plugins. Many SEO plugins add Organisation or WebSite schema automatically.

In my opinion knowing the source of each schema block is just as important as knowing what it contains.

Step Two: List All Schema Types In Use

Once you know where schema is coming from, list the schema types currently active.

Common ones include:

Organisation
LocalBusiness
WebSite
WebPage
Article
BlogPosting
FAQPage
Product
Service
BreadcrumbList

You do not need all of these. What matters is whether the types in use match the site purpose.

From experience I often see sites with LocalBusiness Organisation and Service schema all claiming slightly different business details. That is a red flag.

Step Three: Check For Duplicate Or Conflicting Schema

This is one of the most important steps.

Duplicate schema means the same entity is described more than once in different blocks. Conflicting schema means different blocks describe the same thing differently.

For example:

Two LocalBusiness schemas with different phone numbers
Organisation schema naming one company and LocalBusiness schema naming another
Different addresses across schema blocks
Different logos referenced in different schema

Search engines do not average these out. They lose confidence.

In my opinion it is better to have one clean accurate schema block than three half right ones.

Step Four: Verify Schema Matches Visible Content

This is where most schema fails audits.

Schema must match what users can see on the page. If your schema says you are open Saturdays but the website does not show that, the markup is misleading.

Go through key properties and check them against the page content:

Business name
Address
Phone number
Opening hours
Services offered
Reviews or ratings
Authors and dates on articles

From experience search engines ignore schema that contradicts visible content and repeated contradictions reduce trust overall.

Step Five: Validate Schema Syntax And Structure

Once accuracy is checked you need to confirm the schema is technically valid.

Use the Schema Markup Validator to check syntax and structure.

Look for:

Parsing errors
Missing required properties
Incorrect property types
Invalid nesting

Syntax errors are usually simple issues such as missing commas smart quotes or broken JSON.

I recommend validating at least one example of each page type rather than only the homepage.

Step Six: Use Rich Results Test Where Relevant

Some schema types are eligible for rich results and some are not.

Use Google’s Rich Results Test on pages that contain schema types such as FAQPage Article Product or Review.

Do not panic if a page is not eligible for rich results. That does not mean the schema is useless.

In my opinion the main value of schema is interpretation and trust not visual enhancements.

Step Seven: Review Entity Consistency Across Pages

This step is often overlooked.

Schema helps search engines understand entities. An entity is a real world thing such as a business or person.

Check whether the same entity is described consistently across the site.

For example:

Does the same Organisation appear across all pages
Is the business name identical every time
Are URLs consistent
Is the same logo used
Are social profile links consistent

From experience inconsistent entity signals weaken brand understanding even if individual pages look fine.

Step Eight: Check For Outdated Or Legacy Schema

Legacy schema is common on older sites.

This includes:

Old addresses
Former trading names
Outdated services
Expired offers
Previous authors
Old opening hours

Schema often survives redesigns because it lives in plugins or templates that were never revisited.

In my opinion outdated schema is more damaging than no schema at all.

Step Nine: Assess Whether Schema Types Are Still Appropriate

Not all schema ages well.

A blog that has evolved into a service focused site may still have heavy BlogPosting schema everywhere.

A single location business may have Organisation schema when LocalBusiness would be clearer.

An ecommerce site may still mark up Product pages that no longer exist.

From experience schema audits are an opportunity to simplify not expand.

Step Ten: Prioritise Fixes Based On Risk

Not all issues need fixing at once.

I usually prioritise schema issues in this order:

Conflicting business entities
Inaccurate business details
Schema that contradicts visible content
Duplicate schema blocks
Outdated legacy schema
Missing optional enhancements

Fixing high risk issues first stabilises trust signals quickly.

Step Eleven: Decide Whether To Consolidate Or Remove Schema

This is where judgement matters.

If two schema blocks describe the same thing merge them.

If a schema type no longer serves a purpose remove it.

If a plugin is injecting poor quality schema consider disabling that feature and replacing it with a clean custom implementation.

From experience removing bad schema often improves performance faster than adding new schema.

Step Twelve: Re Test After Changes

After changes are made re test the affected pages.

Validate syntax again. Check Rich Results eligibility again. Confirm visible content still matches schema.

If you are using Google Tag Manager test in preview mode before publishing.

I always recommend keeping a simple log of schema changes so you can trace issues later if needed.

How Often Schema Should Be Audited

Schema audits should not be one off.

In my opinion schema should be reviewed:

After major site changes
After rebrands
After address or phone changes
After plugin updates
At least once a year as part of SEO maintenance

Schema tends to drift quietly over time.

Common Schema Audit Mistakes

I see the same mistakes repeatedly.

Adding new schema without checking existing markup
Fixing syntax but ignoring accuracy
Trusting plugins blindly
Assuming more schema equals better SEO
Not checking multi page consistency

Avoiding these mistakes is often more impactful than learning new schema types.

Schema Audits And AI Visibility

AI driven search systems rely heavily on structured information.

Auditing schema ensures AI systems interpret your site correctly rather than misrepresenting it.

From experience sites with clean consistent schema are summarised more accurately and cited more reliably.

Practical Advice From Experience

If you are auditing schema for the first time start small.

Audit the homepage contact page and one key service page first.

Fix obvious issues then expand.

In my opinion a phased audit beats a perfect plan that never gets executed.

Final Thoughts From Experience

Auditing schema on an existing website is about alignment.

Alignment between code and content. Between pages. Between what you say and what you are.

From experience schema rarely causes dramatic SEO gains on its own. But bad schema quietly holds sites back.

A good schema audit removes friction builds trust and creates a clean foundation for both traditional and AI driven search.

If your site already has schema the most valuable question is not what else can we add but is what we have actually correct.