What Is Review Schema? The Complete Guide (2026)

Why Review Schema Matters for SEO and AI Visibility

According to a 2024 analysis by Moz, pages displaying star ratings in search results achieve a 15–30% higher click-through rate than equivalent pages without ratings. Star ratings signal credibility at a glance — both to human searchers and to AI search systems like Google AI Overviews, which actively surface numerical ratings when answering product and service queries.

AI assistants increasingly pull structured rating data directly from schemas when generating comparison answers. A properly marked-up AggregateRating with a clear ratingValue and ratingCount is far more likely to be cited verbatim than a rating buried in unstructured prose.

Review Schema vs. AggregateRating Schema: What Is the Difference?

These two schema types serve different purposes and are often used together on the same page:

Both can appear as standalone schemas or nested inside a parent type — for example, a Product schema can embed both a review array and an aggregateRating object. Google displays star ratings from either type in rich results.

What Content Types Are Eligible for Review Rich Results?

Google supports Review and AggregateRating rich results for a specific set of content types. As of 2026, the eligible types are:

• Book
• Course
• CreativeWorkSeason
• CreativeWorkSeries
• Episode
• Event
• Game
• HowTo
• LocalBusiness (third-party review sites only — not the business's own site)
• MediaObject
• Movie
• MusicPlaylist
• MusicRecording
• Organization (third-party review sites only)
• Product
• Recipe
• Software App

Reviews for other content types may still be marked up and will be understood by AI systems, but Google will not display them as star-rating rich results in the main Search results page.

Review Schema: Required Properties

Review Schema: Recommended Properties

AggregateRating Schema: Required Properties

The Self-Review Prohibition: A Critical Rule

Google's guidelines state that pages where "the entity being reviewed controls the reviews about itself" are ineligible for the star review rich result. In practice, this means a business publishing reviews about itself on its own website will not earn star ratings — reviews must originate from independent third-party sources.

Greadme specifically checks whether itemReviewed.@type is LocalBusiness, Organization, Corporation, or Restaurant, and when that pattern appears on what looks like the entity's own site, it deducts 30 points and issues a warning. The only legitimate use of Review schema for business types is on independent third-party review platforms.

Decimal Format: Always Use a Dot, Not a Comma

A common internationalization mistake: in some locales, the decimal separator is a comma (e.g., German 4,4). Google requires a period (dot) as the decimal separator for ratingValue in both Review and AggregateRating schemas. Writing "ratingValue": "4,4" instead of "ratingValue": "4.4" causes an error in Greadme and prevents the rating from being eligible for rich results.

Review Schema Code Example

A standalone product review with all required and recommended fields:

{
  "@context": "https://schema.org",
  "@type": "Review",
  "itemReviewed": {
    "@type": "Product",
    "name": "Wireless Headphones X200"
  },
  "author": {
    "@type": "Person",
    "name": "Jane Smith"
  },
  "reviewRating": {
    "@type": "Rating",
    "ratingValue": "4.5",
    "bestRating": "5",
    "worstRating": "1"
  },
  "datePublished": "2026-04-10",
  "reviewBody": "Excellent sound quality with 30-hour battery life."
}

AggregateRating Schema Code Example

AggregateRating nested inside a Product schema — the most common pattern:

{
  "@context": "https://schema.org",
  "@type": "Product",
  "name": "Wireless Headphones X200",
  "image": "https://example.com/x200.jpg",
  "aggregateRating": {
    "@type": "AggregateRating",
    "itemReviewed": {
      "@type": "Product",
      "name": "Wireless Headphones X200"
    },
    "ratingValue": "4.5",
    "bestRating": "5",
    "worstRating": "1",
    "ratingCount": 248
  }
}

Standalone AggregateRating for a Business (Third-Party Site)

This pattern is valid only on a third-party review platform, not the business's own site:

{
  "@context": "https://schema.org",
  "@type": "AggregateRating",
  "itemReviewed": {
    "@type": "LocalBusiness",
    "name": "Sunrise Coffee Roasters"
  },
  "ratingValue": "4.7",
  "bestRating": "5",
  "worstRating": "1",
  "ratingCount": 512,
  "reviewCount": 512
}

Common Mistakes to Avoid

• Missing author.name: The author object must include a name property. An empty author object or one with only @type causes an error.
• Author name exceeds 99 characters: Greadme errors on author names of 100 characters or more — use a real, concise name.
• Promotional author name: Using text like "50% discount until Saturday" as an author name is flagged as an error. Author names must be real person or organization names.
• Missing itemReviewed.@type: Always specify what type of item is being reviewed — Greadme errors if @type is absent from itemReviewed.
• Comma decimal separator: "4,5" causes an error. Always use "4.5".
• Self-reviews on own site: Deducted 30 points and ineligible for rich results.
• Wrong case for property names: reviewrating or itemreviewed will not be recognized. All property names are case-sensitive in JSON-LD.

How Greadme Validates Review and AggregateRating Schema

Greadme runs dedicated validators for both Review and AggregateRating schemas. The validation starts at 100 points and applies the following deductions:

Use Greadme to audit your Review and AggregateRating schemas and see exactly where points are being lost before Google re-crawls your pages.

Review Schema for AI Visibility

AI search engines — including Google AI Overviews, ChatGPT Search, and Perplexity — increasingly use structured rating data to answer questions like "what is the best rated X?" or "how do users rate Y?" A well-formed AggregateRating with a numeric ratingValue and a concrete ratingCount gives AI systems the exact data points they need to generate accurate comparative answers.

In particular, product comparison queries are one of the top citation categories for AI search engines (Princeton/Georgia Tech GEO research, ACM KDD 2024). Pages that combine a Product or LocalBusiness schema with a properly formed AggregateRating are significantly more likely to be cited in AI comparison responses.

Frequently Asked Questions