What is Microdata?

Microdata is one of the two standardised formats (syntaxes) of structured data which can be used with Schema.org to mark up websites. The other is JSON-LD. Microdata uses the Schema.org vocabulary to annotate elements on a page, structuring the data so that it can be understood by search engines. For example, it might be used to show that a particular string of text is an author’s name, and another string of text is a review.