File extension
.md
Markdown
.md files are Markdown documents: a lightweight plain-text markup syntax that stays readable as source while converting cleanly to HTML, widely used for READMEs, documentation, notes, and static sites.
Known meanings
Formats and reference material for .md
Markdown
Lightweight plain-text markup that converts to HTML
Details
Format notes
Markdown
Markdown is a lightweight markup language created by John Gruber with the goal that
the source text should be as readable as possible on its own, while still converting
cleanly to HTML. Instead of tags, it uses unobtrusive punctuation conventions — #
for headings, * or _ for emphasis, - for list items, backticks for code, and
[text](url) for links — so a .md file reads naturally in a plain editor and
renders as formatted output when processed. This balance made it the default format
for software READMEs, documentation, wikis, forum and chat messages, note-taking
apps, and static-site generators.
Because the original description left some behavior unspecified, many implementations diverged, and the CommonMark specification was created to define Markdown precisely and improve interoperability. Popular supersets such as GitHub Flavored Markdown add tables, task lists, strikethrough, and fenced code blocks with syntax highlighting.
Extensions And Front Matter
Markdown is frequently combined with other conventions: a YAML “front matter” block at the top of a file carries metadata for site generators, and many toolchains allow embedded raw HTML for anything Markdown itself does not express. As a result the exact feature set depends on the processor, which should be recorded for reproducibility.
Preservation And Security Notes
Markdown is ideal for preservation: it is open, plain text, human-readable even
without rendering, and diff-friendly for version control. When converting Markdown
from untrusted sources to HTML, sanitize the output (and any embedded raw HTML) to
prevent cross-site scripting. The common media type is text/markdown.
Further Reading
- CommonMark specification:
https://commonmark.org/ - GitHub Flavored Markdown spec:
https://github.github.com/gfm/