‍Structured data refers to any data that is organized in a way that can be easily understood by machines.

In the context of web development and SEO, structured data usually refers to specific formats and vocabularies that provide information about a webpage and its content.

It typically involves JSON chunks, or specific HTML vocabularies that tell search engines exactly what each part of the content means and how it should be treated.

Let's say you have a webpage about a movie. You can use schema markup to tell search engines that the page is about a movie, that the title of the movie is "Bladerunner", that it was released in 1982, that the director is Ridley Scott, and so on.

In microdata format, this might look like;

In this example, itemscope and itemtype are used to specify that the <div> is a Movie, and itemprop is used to specify the properties of the movie (the name, director, actors, release date, and description).

Types of Structured Data

There are several types of structured data;

• Microdata: Microdata is a specification used to nest structured data within HTML content. Schema.org is a popular vocabulary that is often used with Microdata. The example above demonstrates this.
• JSON-LD: JSON-LD ( JavaScript Object Notation for Linked Data ) is a method of encoding Linked Data using JSON. It's recommended by Google and is commonly used for structuring data in a variety of web applications.
• RDFa: RDFa ( Resource Description Framework in Attributes ) is an extension to HTML5 that helps to incorporate structured data into HTML documents.
• Microformats: Microformats are small patterns of HTML to represent commonly published things like people, events, blog posts, reviews and more.

And technically, META tags also describe structured data;

• Open Graph: Open Graph is a protocol that allows a webpage to become a rich object in a social graph, used primarily for integration with Facebook and other social media platforms.
• Twitter Cards: Similar to Open Graph, Twitter Cards allow for the addition of structured data specifically for presenting webpage content within Twitter.

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Best Practices

• Use Google Search console, as it is excellent at telling you what it see and where it discovers errors.
• Review the console regularly, Google does change how it parses the snippets, and you may need to modify them in the future.