In addition to image uploads and code formatting, I also needed the ability to:
All of this metadata was information I wanted to track for each markdown file, but I didn't want to keep the metadata outside of the markdown file in a separate store, because synchronization only adds complexity. I was looking for a way to embed metadata into the markdown file itself, but the CommonMark specification doesn't provide for metadata.
Fortunately, I found a number of tools and libraries support YAML front matter in markdown. Front matter is easy to write, easy to parse, and a good solution if you need to keep metadata associated with your markdown with you markdown.
The picture below shows a post after publication, so the tools have added an ID and a URL. I add the date to publish and the title.