Use the Structured Data Analyzer Tool
The Structured Data Analyzer was designed to crawl a site to determine if structured data (aka schema markup) is present. It discovers both JSON-LD and Microdata, even if it is being loaded asynchronously in a tag and tells you if there are errors or warnings for Google required and recommended properties. Software maintenance typically contributes to ~75% of the total cost of ownership. Let us stay on top of the updates for you!