A Markdown preview tool lets you write Markdown text and see the rendered HTML output in real-time. This is essential for writing README files, documentation, blog posts, and any content that will be rendered as Markdown. The live preview lets you see exactly how your formatting will appear before publishing.

This tool runs entirely in your browser — your Markdown text is parsed client-side using JavaScript and never sent to any server. The preview updates instantly as you type, with no lag or delay.

Headings: Use # for h1, ## for h2, ### for h3. Bold: Wrap text in **double asterisks**. Italic: Wrap text in *single asterisks*. Code: Use `backticks` for inline code and triple backticks for code blocks. Links: [link text](url). Lists: Start lines with - or * for bullet points. Blockquotes: Start lines with >. Horizontal rules: Three dashes ---.

Markdown was designed by John Gruber with the philosophy that the source text should be as readable as possible without rendering. This makes it ideal for version control (Git), plain text editing, and content that may be consumed in both rendered and raw forms.

The editor is split into two panels. Write your Markdown in the left panel and see the live HTML preview in the right panel. The preview updates instantly as you type. A sample document is provided to demonstrate the supported syntax.

Use the 'Copy HTML' button to copy the rendered HTML output — useful for pasting into email editors, CMS systems, or any context that accepts HTML. The HTML output includes semantic tags (h1-h3, strong, em, code, pre, ul, li, blockquote) with CSS classes for easy styling.

Markdown has become the standard for developer documentation. GitHub renders Markdown files (README.md, CONTRIBUTING.md) automatically. Static site generators like Hugo, Jekyll, Gatsby, and Next.js use Markdown for content. Documentation frameworks like Docusaurus, VitePress, and MkDocs are built entirely around Markdown.

For a full-featured Markdown writing experience, Obsidian (obsidian.md) is an excellent free desktop app with bidirectional linking, graph views, and an extensive plugin ecosystem. Notion (notion.so) combines Markdown-style editing with databases and collaboration. For focused writing, iA Writer (ia.net/writer) offers a distraction-free Markdown editor with beautiful typography.

For advanced needs, CommonMark provides a strict specification for Markdown parsing, and GitHub Flavored Markdown (GFM) adds extensions like tables, task lists, strikethrough, and auto-linking. This tool supports the core CommonMark syntax that works across all Markdown processors.