Which file types Unmarked opens

Unmarked opens .md, .markdown, .mdown, .mkd, and plain .txt files, reading each one as Markdown. Nothing to convert, nothing to import.

The extensions

Markdown files ship under different extensions depending on the tool that made them. Unmarked opens the common ones:

• .md
• .markdown
• .mdown
• .mkd
• .txt

The .txt case is the one people miss. A Markdown file is plain text with formatting characters inside it, like # for a heading or - for a list. So a .txt file written in Markdown opens and renders exactly like a .md file. If your notes live in .txt, point Unmarked at them.

The Markdown it understands

Whatever the extension, each file opens as CommonMark plus the GitHub extensions most people use, tables, task lists, strikethrough, and YAML frontmatter. A real-world file from GitHub, Obsidian, or a static-site project looks right the first time you open it. For the exact syntax that renders, see what Markdown Unmarked renders.

Files it won't open

Unmarked reads text, not binaries. It declines binary files and anything over 25 MB rather than risk corrupting them, on purpose. Hand it a Word .docx or a PDF and it won't try to read it as text. To get a document into Markdown, convert it first, then open the result.