Google announced that it’s okay to merge two kinds of Schema.org structured data now and that it will validate at the major structured data validators.
Now your choices aren’t restricted to exclusively using JSON-LD or Microdata structured data. It’s unclear if RDFa is included although it’s said to validate.
Syntax Graph Merge
Aleyda Solis tweeted the news from Google Search Central Live in Zurich where the announcement was made.
Google made a soft launch last week without announcing it until today.
What This Means In Plain English
The impact is limited to specific use cases where it makes sense. Otherwise if using one type of Schema.org structured data works for you, continue using it.
There are however other use cases where it makes sense to use Schema.org JSON-LD and Microdata format
Difference Between JSON-LD and Microdata Structured Data
JSON-LD is a script that can go in the head section of the HTML (along with other meta data like the title and description) or it can go anywhere in the body of the webpage. JSON-LD structured data is preferred because it’s easy to maintain, easy to read and troubleshoot and is separate from the HTML.
Microdata is markup that integrates with HTML as attributes of elements.
This means, for example, that you can have a heading element (H1, H2, etc.) that could contain a Microdata attribute.