JSON-LD (JavaScript Object Notation for Linked Data) is a lightweight data-interchange format that is easy for humans to read and write, as well as easy for machines to parse and generate. Its used to structure and link data on the internet. For webpage schema markup, using JSON-LD is important because it allows webmasters to embed structured data within the context of a webpage, which helps search engines better understand the content and context of the pages, potentially leading to richer search results and improved findability.