Schema markup (structured data)

What schema markup is, why it earns rich results, and how to add JSON-LD schema to WordPress with the ACF plugin.

What is schema markup?

Schema markup (structured data) is code added to a page that helps Google understand its content more precisely. When Google reads it, it can display rich results — star ratings, FAQs, event info — directly in search results, improving visibility and click-through rate (CTR).¹

Why add structured data

Helps Google understand content more clearly.
Improves how pages appear in results (featured snippets, knowledge panels).
Increases the chance of rich snippets.
Strengthens SEO and site credibility.

How it works

With a format like JSON-LD, Google extracts and displays enhanced information instead of reading only plain text. Example: an "Article" schema can surface the author name, published date, headline, thumbnail image, and ratings directly in the result.

Supported format: JSON-LD (JavaScript Object Notation for Linked Data) — Google's recommended format, and the one to always use.

Adding schema in WordPress with ACF

Install ACF (Advanced Custom Fields) — Plugins → Add New → search "ACF — Advanced Custom Fields" → Install → Activate.
Create a custom field for schema — Custom Fields → Add New, name it "Schema Markup", add a field of type Text Area named schema, set location rules to Post Type = Post and Post Type = Page, and publish the field group.
Generate the schema code — ask an AI tool for JSON-LD (Article, FAQ, Product, etc.) and copy the result.
Paste it into functions.php — Appearance → Theme File Editor → functions.php, and add:

function add_custom_schema_to_head() {
  if (is_single() || is_page()) {
    $schema = get_field('schema');
    if (!empty($schema)) {
      echo '<script type="application/ld+json">' . $schema . '</script>';
    }
  }
}
add_action('wp_head', 'add_custom_schema_to_head');

This pulls the schema from the ACF field and outputs it in the page's <head>.

Optional: online schema generators can auto-generate schema (Video, Article, Product) from a pasted link — paste the resulting code into the ACF field on the post/page.

Testing schema

Use Google's Rich Results Test (or the Structured Data Testing Tool). A green tick means the schema is valid — always test before publishing.

Important notes

The schema must match the actual visible content on the page.
Never use fake or misleading structured data — it risks a manual penalty.
Visible content (title, author, date) should match what the schema claims.
Use an AI tool to help generate or validate clean JSON-LD for your case.

Rank Math SEO plugin

A separate lecture covers setting up Rank Math for schema support, canonical tags, and meta settings — follow that lecture for the plugin-specific setup.

Summary

Schema markup improves SEO and helps content stand out visually in search.
The ACF + functions.php method adds custom schema manually.
Generate schema from trusted tools or AI, and always test before shipping.
Article, Video, Product, and FAQ schema can each boost ranking and visibility.

iSkills SEO course notes, compiled 2025. ↩

Schema markup (structured data)

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