Markdown Tools and Converters

Markdown succeeded because its source is readable without being rendered. A heading looks like a heading, a list looks like a list, and emphasis is visible as asterisks. That is why it became the format for READMEs, documentation and issue trackers.

It is deliberately limited, covering only common document structures. Anything beyond them requires embedded HTML, which is where the security consideration comes in: a Markdown document from an untrusted source can contain a script tag, so converting it without escaping raw HTML creates a cross-site scripting vector.

Flavour differences are worth knowing. CommonMark pinned down the core syntax, but tables, task lists and strikethrough are GitHub extensions rather than part of it, and footnotes or math vary by renderer. A document relying on those may render differently elsewhere.