What is Markdown and who created it?

Markdown is a lightweight markup language created by John Gruber and Aaron Swartz in 2004. It lets you write formatted text using plain-text syntax that is easy to read and write. Markdown files use the .md or .markdown extension and are widely used for documentation, README files, blogs, and static-site content. The syntax maps directly to HTML elements, so headings become <h1> – <h6> , asterisks produce emphasis, and so on.

Markdown vs HTML — when should I use which?

Use Markdown when you need quick, readable content authoring — documentation, notes, blog posts, or README files. Use HTML when you need precise control over layout, semantic elements, or interactive features. In practice the two work together: you write in Markdown for speed, then export to HTML for publishing. You can validate the exported HTML to make sure the output is well-formed and accessible.

What is GFM (GitHub Flavored Markdown)?

GFM is a superset of CommonMark maintained by GitHub. It adds features that developers rely on every day: fenced code blocks with syntax highlighting, task lists ( - [x] ), tables, strikethrough text, and autolinked URLs. Most modern Markdown renderers — including this editor — support GFM out of the box, making it the de-facto standard for technical writing.

How do I add tables, code blocks, and images in Markdown?

For tables , use pipes and hyphens: | Header | Header | followed by | --- | --- | and data rows. For fenced code blocks , wrap code in triple backticks and optionally specify a language ( ```js ) for syntax highlighting. For images , use ![alt text](url) . All three render instantly in the live preview pane of this editor.

Can I export Markdown to HTML or PDF?

Yes. This editor lets you export your Markdown as sanitized HTML with a single click. From there you can paste the HTML into any CMS, email builder, or static-site generator. For PDF output, open the HTML in a browser and print to PDF — or pipe it through a tool like Puppeteer or wkhtmltopdf. After exporting, you can validate the exported HTML for correctness, or use our Diff Checker to compare markdown versions side by side.

How do I prevent XSS when rendering user-submitted Markdown?

Never render raw Markdown-to-HTML output without sanitization. Markdown parsers like marked or markdown-it can emit raw HTML including <script> tags. Always post-process with a sanitizer like DOMPurify or sanitize-html that strips dangerous elements and attributes (event handlers, javascript: URLs). This editor uses DOMPurify under the hood. You can validate the sanitized HTML output for correct structure.

Markdown Editor & Preview

Free online Markdown editor with live preview, GFM support, syntax highlighting, and HTML export

Markdown

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Frequently Asked Questions

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HTML

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Markdown Editor & Preview

Markdown

Preview

Frequently Asked Questions

What is Markdown and who created it?

Markdown vs HTML — when should I use which?

What is GFM (GitHub Flavored Markdown)?

How do I add tables, code blocks, and images in Markdown?

Can I export Markdown to HTML or PDF?

How do I prevent XSS when rendering user-submitted Markdown?

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Frequently Asked Questions

What is Markdown and who created it?

Markdown vs HTML — when should I use which?

What is GFM (GitHub Flavored Markdown)?

How do I add tables, code blocks, and images in Markdown?

Can I export Markdown to HTML or PDF?

How do I prevent XSS when rendering user-submitted Markdown?