Markdown Preview
Turn Markdown into a readable preview and a downloadable HTML document.
Local processing · Up to 100,000 characters. Raw HTML appears as text; images appear as labels.
About Markdown Preview
This tool turns Markdown into formatted HTML in your browser using the marked library with GitHub-flavoured extensions: headings, lists, tables, strikethrough, task lists, blockquotes, links and code blocks. Press Render preview to see the result, then download it as a standalone HTML document or save the Markdown itself. The output is sanitised before it is shown. Raw HTML in your source is not executed: it is escaped and displayed as literal text. The result then passes through DOMPurify with a short allowlist of tags (headings, paragraphs, lists, tables, links, code, task-list checkboxes) and attributes, so scripts, event handlers and styles are removed. Images are never fetched. An image becomes a text label such as [Image: description], so previewing a document cannot trigger a request to another server, and the exported HTML also hides any image elements and carries a restrictive Content-Security-Policy. Ordinary links stay clickable. Not supported: syntax highlighting, maths, and rendering of embedded HTML. The editor accepts up to 100,000 characters, and you can open a UTF-8 .md, .markdown or .mdown file of up to 400,000 bytes. Nothing is uploaded; the source stays local. Use it to check a README, a changelog or an article draft before publishing, or to produce a clean HTML copy of a note.
How to use Markdown Preview
- Type or paste Markdown into the Markdown source box, or use Open a Markdown file to load a .md, .markdown or .mdown file.
- Press Render preview to generate the sanitised preview below the editor.
- Check headings, tables, links and code blocks in the Rendered preview panel, and edit the source if anything looks wrong.
- Use the HTML export to download a standalone document, or the Markdown export to save the source. Clear empties the editor.
Frequently Asked Questions
No. Raw HTML is escaped and shown as text, and the output is sanitised with DOMPurify, which removes scripts, event handlers and disallowed tags. Only a small allowlist of formatting tags survives into the preview.
To keep the preview from making requests to other servers, each Markdown image is replaced with a label like [Image: description]. Nothing is downloaded. The exported HTML also hides image elements.
CommonMark-style Markdown plus GitHub-style tables, strikethrough and task lists. Syntax highlighting, maths and raw HTML rendering are not included. Input is limited to 100,000 characters.
Press Render preview, then use the HTML download below the preview. You get a standalone .html file containing the sanitised result with basic styling and a restrictive Content-Security-Policy. You can also download the original Markdown.
No. Rendering and file reading happen in your browser, and the source stays on your device. Files you open are read locally, in UTF-8, up to 400,000 bytes.
Yes. Ordinary links that pass sanitisation can be followed when you click them. Unsafe link types, such as javascript: URLs, are stripped by the sanitiser, so they will not appear as working links.