I/O operations with PHP/MySQL - I'm stuck

> storageManager: {
    type: 'remote',
    urlStore: 'http://endpoint/store-template/some-id-123',
    urlLoad: 'http://endpoint/load-template/some-id-123',    
  }

> {
  // `gjs-` is the id prefix
  'gjs-components': [{ tagName: 'div', ... }, {...}, ...],
  'gjs-style': [{...}, {...}, ...],
}

My problem is that I'm trying to get the HTML to JSON conversion formatted properly before saving to the db record so we can pull it up again from urlLoad. I can't find ANY clear examples of how to do this from PHP. I could try using the Firestore plugin and save myself the trouble, but I thought I'd ask if there were any clear examples of how to do I/O operations with PHP/MySQL.

Maybe using HTML-5 html2json (http://masterminds.github.io/html5-php/) would help? Or does GrapesJS automatically do the HTML to JSON/DOM conversion on the fly? It's not clear to me from the docs.