Markdown Preview
Write Markdown on the left, see a beautiful live preview on the right. Export as HTML, download as .md, or copy rendered output. Everything runs in your browser.
Free Online Markdown Editor with Live Preview
Our Markdown Preview tool gives you a real time, side-by-side editing experience. Write standard Markdown syntax on the left and instantly see the rendered HTML output on the right. Ideal for writing README files, documentation, blog posts, and notes.
What is Markdown?
Markdown is a lightweight markup language created by John Gruber in 2004. It lets you format text using simple, readable syntax that converts to HTML. It is the standard format for README files on GitHub, GitLab, and Bitbucket, and is widely used in documentation, blogging platforms, and note-taking apps.
Features
- Live Preview - See rendered HTML update in real time as you type
- Formatting Toolbar - Quick-insert bold, italic, headings, links, images, code blocks, lists, quotes, and tables
- Syntax Highlighting - Code blocks are highlighted with highlight.js for over 190 languages
- Export as HTML - Download a complete HTML file with inline styles
- Copy Rendered HTML - Copy the HTML output to paste into emails, CMS editors, or documents
- Download as .md - Save your Markdown source as a file
- Word Count - Live word and character count displayed in the toolbar
- Fullscreen Mode - Expand the editor for distraction-free writing
- 100% Client-Side - Your text never leaves your browser. No data is sent to any server.
Supported Markdown Syntax
This editor supports the full CommonMark specification plus GitHub Flavored Markdown (GFM) extensions including tables, strikethrough, task lists, and autolinks. Code blocks with language identifiers receive automatic syntax highlighting.
Live Markdown Preview: What to Watch For
Markdown is the lingua franca of developer documentation: README files, GitHub issues, Notion docs, blog posts, internal wikis. Almost every renderer claims to be CommonMark-compliant, yet the smallest details — table borders, footnote rendering, GitHub-flavored extensions — vary across tools. Previewing in the same flavor your final destination uses prevents surprises.
The major Markdown flavors
- CommonMark. The 2014 standardization effort. The strict baseline.
- GitHub-Flavored Markdown (GFM). CommonMark + tables, task lists, autolinking, strikethrough, fenced code blocks with syntax highlighting.
- MDX. Markdown with embedded JSX components. Used heavily in Docusaurus, Next.js, Astro.
- Markdown Extra (PHP). Adds attribute lists, footnotes, definition lists.
- R Markdown / Quarto. Adds YAML headers, code-execution blocks, citations.
If you're shipping to GitHub, preview in GFM. If to Notion, preview with Notion's quirks (it doesn't support footnotes, has its own block structure). One markdown source rarely renders identically in two places.
Things that frequently break
- Inline HTML. Some renderers strip it for security. Others render it. If your readme has a
<table>, expect different appearances. - Code fence languages. Highlighting depends on the renderer's lexer set.
```rustworks on GitHub but not on every static site generator. - Math (LaTeX). GitHub supports KaTeX in
$...$blocks. Most blogs require explicit MathJax / KaTeX integration. - Mermaid diagrams. GitHub renders them. Most renderers don't.
- Soft line breaks. A single newline can become a
<br>(GFM) or be ignored (CommonMark). Surprising in lists. - Image sizing. CommonMark has no syntax for it. Every renderer that supports it uses a different convention.
Workflow recommendations
- Pick the target (GitHub README, Notion, your blog) before writing.
- Preview in the same flavor — not whatever your editor defaults to.
- Test on mobile width — long tables and pre blocks blow out viewports.
- Check accessibility — alt text on images, real heading hierarchy, no skipped levels.
- For long documents, generate a TOC and verify anchor links.
Pitfalls
- Mixing tabs and spaces in code blocks. Renderers differ on whether they preserve. Convert to spaces with your editor.
- Trailing whitespace. Two trailing spaces = line break. Easy to lose to "trim trailing whitespace on save".
- Smart quotes. Some renderers convert
"foo"to"foo", breaking copy-pasted code blocks.
This preview is GFM-compatible and renders entirely in your browser. For documentation pipelines, see our developer tools roundup.
Frequently Asked Questions
Which Markdown flavor should I write in?
Match your destination. GitHub: GFM. Static site generator: whatever it ships with (usually CommonMark + a few extensions). Notion: write through Notion's UI; importing Markdown loses fidelity.
Why does my table look different on different sites?
Tables are not in CommonMark — they are an extension. GFM, Markdown Extra, and various SSGs each implement them slightly differently.
Can I include diagrams?
GitHub renders Mermaid in fenced code blocks tagged "mermaid". Most other renderers need a plugin.
Is my Markdown sent to a server for preview?
No. Rendering happens in your browser using a JavaScript Markdown library.