MarkText is a free and open-source realtime preview markdown editor which support both CommonMark Spec and GitHub Flavored Markdown Spec. It is a concise text editor, dedicated to improving your writing efficiency.
Features:
It's a great program but does not have maintainers since around july 2022. See this post: https://github.com/marktext/marktext/issues/1290#issuecomment-1172914762
Imo it's one of the four best markdown apps (no specific order: MarkText, Logseq, Typora, Obsidian)
Finally, an open source alternative to Write! app (chich was great, but necessitates an account and not supported anymore) that looks clean to use, with great text options. It's really fine so far and I really look forward using it plently.
Very usable, stable, never crashed or gave any problem. There are still a bit of little things to polish (scrolling, copy & paste), but it's an excellent markdown editor. This tool is similar to Typora.
Can't see where the editor stops and the windows behind it begin. Far too early in the development stage for me ATM.