Schema Markup for SEO: JSON-LD, Key Types and What It Really Does

Schema markup for SEO is structured data, written in the schema.org vocabulary, that tells search engines exactly what a page is about: which organization published it, what product it sells, where a business is located, who wrote an article and when. It does not raise rankings by itself; its job is to make a page eligible for rich results in Google Search and to remove guesswork about the entities on the page.

That distinction matters more in 2026 than it used to. Google has retired several rich result types, including FAQ rich results in May 2026, and it states plainly that no special schema is needed to appear in AI Overviews or AI Mode. What remains is a smaller, clearer set of markup that is worth doing properly. This guide covers what schema is, why JSON-LD is the format to use, the five types most sites need, how to validate them, and what schema can and cannot do for you.

What schema markup is

Schema.org is a shared vocabulary of types (such as Organization, Article, Product, LocalBusiness) and properties (such as name, address, price, author). When you add schema markup to a page, you describe its content in that vocabulary in a machine-readable form, separate from the visible text.

A human reading a product page can see the price, the brand and whether the item is in stock. A crawler can usually work that out too, but it has to infer it from layout and wording. Structured data states it explicitly: this is a Product, its name is X, its offer has a price of Y in currency Z, and its availability is InStock. Google uses that information to understand the page and, for supported types, to build enhanced search results such as product prices, review stars, breadcrumbs, event dates or business details.

JSON-LD, Microdata and RDFa: which format to use

Google supports three formats for structured data:

• JSON-LD, a block of JSON placed in a script element of type application/ld+json, either in the head or the body of the page.
• Microdata, attributes added to the existing HTML elements that wrap the content.
• RDFa, another attribute-based approach that extends HTML.

Google's documentation says that in general it recommends JSON-LD where a site's setup allows it, because it is the easiest to implement and maintain at scale. The reason is practical: JSON-LD lives in one block, so developers can generate it from the CMS or database without touching the visible template, and editors cannot break it by changing a heading.

Two implementation details trip people up. First, the JSON must be valid JSON, with straight double quotes and no trailing commas. Second, use standard JSON escaping rather than relying on HTML entities: since August 2026 Google applies only a single pass of HTML unescaping when it extracts JSON-LD, so entities that a template engine has escaped twice are no longer decoded to the intended characters.

The schema types most websites need

Schema.org has hundreds of types, but Google only builds search features from a limited list, published in its Search Gallery. For most business sites, five types cover nearly everything.

Organization

Organization markup describes the company itself: name, url, logo, sameAs links to official profiles, address, telephone and contact points. Google's documentation says there are no required properties and recommends adding as many relevant ones as you can. It also says the markup belongs on the home page or a single page about the organization, such as the about page; it does not need to be on every page. The logo should be at least 112x112 pixels.

Article

Article markup (or its subtypes NewsArticle and BlogPosting) describes editorial content: headline, image, datePublished, dateModified and author. Google lists no strictly required properties for Article, but the author and date properties are what make the markup useful. Make sure the dates match the dates printed on the page, and that the author is a real person or organization with a page of their own where possible.

Product

Product markup describes items for sale or review. Google separates two uses. Product snippets cover pages such as reviews and comparison pages; they require the product name plus at least one of review, aggregateRating or offers. Merchant listings cover pages where a shopper can actually buy the product, and they have their own requirements and their own Search Console report. An online store's product pages fall into the merchant listing case.

LocalBusiness

LocalBusiness markup (and subtypes such as Restaurant or Dentist) describes a physical location. Google requires name and address, and recommends properties such as telephone, url, geo coordinates, openingHoursSpecification and priceRange. Google notes that review and aggregateRating on LocalBusiness are only recommended for sites that capture reviews about other local businesses, so a business marking up its own star rating on its own site should not expect a review snippet.

FAQPage, and what changed in 2026

FAQ markup used to be the most common way to win extra space in search results. Google stopped showing FAQ rich results in Google Search from 7 May 2026 and removed the feature from its documentation in June 2026. FAQPage is still valid schema.org vocabulary, and markup that matches visible questions and answers does no harm, but it will not produce a Google search feature any more. HowTo rich results were retired earlier. If FAQ snippets were the main reason a site added schema, it is time to refocus on the types Google still supports.

How to add schema markup to a page

1. Choose the type from the visible content. Ask what the page is. A service page is usually part of the Organization or LocalBusiness story, not a Product. A blog post is an Article.
2. Fill required properties first, then the recommended ones you can keep accurate. Google's guidance is that fewer complete and accurate recommended properties beat many incomplete or wrong ones.
3. Generate it from the source of truth. Prices, stock status, opening hours and dates change. Hard-coding them into a template guarantees they will drift out of date. Pull them from the same database that renders the page.
4. Connect entities with @id. Give the Organization a stable @id and reference it as the publisher of every Article. This tells crawlers that the same company sits behind all the content.
5. Only mark up what users can see. Google's structured data policies say not to mark up content that is not visible to readers and not to create pages just to hold structured data.

Most CMS platforms and SEO plugins output Organization and Article markup automatically. Check what is already there before adding more, because duplicate or conflicting blocks for the same entity create confusion rather than clarity.

How to validate schema markup

Use three checks, in this order:

• Rich Results Test. Google's tool shows which Google search features the page is eligible for and lists errors and warnings against Google's requirements. It only reports on Google-supported features.
• Schema Markup Validator. The schema.org validator checks any schema.org markup against the vocabulary itself, including types Google does not use for rich results.
• Search Console reports. After deployment, the rich result status reports (for example Products, Merchant listings, Breadcrumbs) show valid and invalid items across the whole site, and the URL Inspection tool shows what Google detected on a single live URL.

Errors stop a page from being eligible for a feature. Warnings mean a recommended property is missing; the page can still be eligible. Even valid markup carries no promise: Google says it does not guarantee structured data will show up in search results, even when it is correct.

What schema does and does not do for rankings and AI answers

What it does. Schema makes a page eligible for rich results, which can change how a listing looks and how much space it takes. It gives Google an unambiguous statement of entities, prices, dates and locations. It also makes your own data easier to reuse in places like merchant listings.

What it does not do. Schema is not a ranking boost. Google's own structured data guidelines are explicit: a structured data manual action removes a page's eligibility for rich results but does not affect how the page ranks in web search. For AI features, Google's guidance says there are no additional requirements to appear in AI Overviews or AI Mode, and no special schema.org markup you need to add; pages need to be indexed, eligible for a snippet and built on normal SEO fundamentals.

In other words, schema supports understanding and presentation. Content quality, crawlability, internal linking and authority still decide whether the page ranks or gets cited. Treat any claim that a particular markup type guarantees AI visibility with suspicion, and look instead at generative engine optimization work that improves the content itself.

Common schema mistakes

• Marking up reviews or ratings that are not shown on the page, or self-serving review markup on your own business.
• Prices, availability or dates in the markup that disagree with the visible page.
• Two plugins each outputting their own Organization block with different names or logos.
• Product markup on service pages that do not sell a specific product.
• Keeping FAQ markup as the main SEO tactic after the rich result was retired.

An SEO audit is the usual place to catch these at site scale, since a crawl can list every page's structured data and flag conflicts.

Schema markup for Thai websites

Schema.org property names stay in English on Thai sites; only the values change. A Thai page can describe a business with a Thai name and Thai street address in LocalBusiness, while the property keys stay as name and address. Bilingual sites should mark up each language version with values in that language and set inLanguage on Articles, so the Thai page describes itself in Thai rather than repeating the English values. Use the Thai address format consistently with the business profile and other listings, since the same name, address and phone number across sources helps local search. For Thai businesses with physical branches, LocalBusiness markup on each branch page works best alongside a well-maintained Google Business Profile and local SEO work.

Frequently asked questions about schema markup for SEO

Does schema markup improve Google rankings?

No, schema markup is not a direct ranking factor; it makes pages eligible for rich results and helps Google understand them. Google's own policy confirms that a structured data manual action affects rich result eligibility, not web search ranking.

Do I need schema markup to appear in Google AI Overviews?

No, Google says there is no special schema.org markup required for AI Overviews or AI Mode. A page needs to be indexed, eligible to show a snippet and built on sound SEO fundamentals.

Is FAQ schema still worth adding?

FAQ schema no longer produces a rich result in Google Search, which stopped showing FAQ rich results in May 2026. It is harmless where it matches visible questions and answers, but it should not be a priority.

Which format should I use for structured data?

Use JSON-LD, which Google recommends wherever a site's setup allows it. It sits in one script block, is easier to generate from a CMS, and is less likely to break when page templates change.

How do I check whether my schema markup works?

Run the page through Google's Rich Results Test for Google features and the Schema Markup Validator for general schema.org errors. After launch, monitor the rich result reports and URL Inspection in Search Console.

Get your structured data checked

Schema markup is a small part of technical SEO, but a broken or conflicting implementation can quietly cost a site its product, review or business features in search. If you want Organization, Article, Product and LocalBusiness markup reviewed and fixed as part of a wider plan, see the SEO services in Thailand offered by Relevant Audience.