Markdown to HTML renders Markdown as you type and lets you copy the HTML or download a standalone document. It covers the common CommonMark set plus GitHub extensions: tables, task lists, strikethrough, and autolinks.
Everything runs in the page. Raw HTML in your Markdown is escaped and shown as text, so the preview cannot run scripts. Nothing is uploaded.
No. It is escaped and rendered as text, which keeps the preview safe.
GitHub-style tables with alignment, task lists, strikethrough, and autolinks, on top of standard Markdown.
Reference-style links, footnotes, definition lists, and setext (underlined) headings.
No. The conversion runs in JavaScript in the open tab.