Markdown → HTML

Markdown is a lightweight markup language created by John Gruber in 2004, designed to be readable as plain text while converting cleanly to HTML. The core syntax covers common formatting needs: # through ###### for headings, **bold** and *italic*, `inline code` and fenced code blocks, [links](url) and , and - or * for unordered lists and 1. for ordered lists.

GitHub Flavored Markdown (GFM) is the most widely used Markdown variant, extending the original syntax with tables, task lists (- [ ] and - [x]), strikethrough (~~text~~), autolinked URLs, fenced code blocks with language identifiers for syntax highlighting, and @mentions. GFM has become a de facto standard for developer documentation because GitHub's influence made it the expected format for README files and wiki pages.

Markdown is used pervasively in software development: README files, GitHub and GitLab wikis, Confluence documentation, static site generators (Hugo, Jekyll, Gatsby, Astro), documentation tools (MkDocs, Docusaurus), note-taking applications (Obsidian, Notion), and many content management systems. When rendering user-authored Markdown to HTML, always sanitize the output to prevent XSS — raw HTML in Markdown is allowed by the original spec and can be a security risk if user input is not sanitized.