StackEdit is described as 'free, open-source Markdown editor based on PageDown, the Markdown library used by Stack Overflow and the other Stack Exchange sites. Rich Markdown editor' and is a popular app in the Development category. There are more than 50 alternatives to StackEdit for a variety of platforms, including Mac, Windows, Linux, Online / Web-based and Android. The best alternative is Joplin, which is both free and Open Source. Other great apps like StackEdit are Typora (Free), Zettlr (Free, Open Source), Mark Text (Free, Open Source) and ghostwriter (Free, Open Source).
Joplin is a free, open source note taking and to-do application, which can handle a large number of notes organised into notebooks. The notes are searchable, can be copied, tagged and modified either from the applications directly or from your own text editor.
Zettlr is a supercharged markdown editor that combines many writing editor features and collect them in one application. It aims at speeding up your workflow and help you write without any interruptions.
No excuses. No distractions. Just write. ghostwriter is a feature-rich text editor using Markdown syntax which makes it suitable for note-taking, document redaction, simple HTML website creation and much more.
Haroopad is a markdown enabled document processor for creating web-friendly documents. You can author various formats of documents such as blog article, slide, presentation, report, and e-mail as if experts did.