GitHub-flavored Markdown and Slack mrkdwn share 60 percent of their grammar. The other 40 percent is where release notes, runbooks, and incident postmortems spend their time, and that is exactly where the converter at Markdown to Slack mrkdwn earns its keep.
A free browser-based PDF to Markdown converter that runs entirely client-side — extract headings, lists, tables, and code blocks from any PDF without uploading a single byte to a server.
A markdown converter looks trivial until it isn't. The value of a good one is making the seven small decisions visible so you can make them on purpose.