Markdown to HTML converter.

What this converts

The converter is markdown-it 15.0.2 (MIT licence, bundled with this site, no network call) in its commonmark preset, which implements the CommonMark 0.31.2 specification. With the GitHub option ticked it also enables pipe tables and ~~strikethrough~~ from GitHub Flavored Markdown, and a small rule that turns - [ ] and - [x] list items into disabled checkboxes. All specification pages and the library repository were read on 1 October 2026.

How the output is sanitised

• Raw HTML is never passed through. The library runs with html: false, so <script>, <img onerror=...> and any other tag you type is escaped and shown as literal text. That is stricter than CommonMark, which allows raw HTML, and it is why no on* attribute can reach the output.
• Unsafe link targets are refused. markdown-it rejects javascript:, vbscript:, file: and most data: targets, so [x](javascript:alert(1)) stays as plain text instead of becoming a link. Image data: URLs are only allowed for GIF, PNG, JPEG and WebP.
• One caveat: this is protection for the HTML this page generates. If you paste it into another system, that system's own sanitiser and content policy still apply, and the converter does not check where your https: links point.

Worked example

Press Load example. The input is a heading, a two-item task list, a two-column table with a centred second column, a line with ~~old~~ **new** and a link, and two deliberately unsafe pieces: a <script> tag and a javascript: link. The output is an <h1>, a <ul> of two checkbox items (one checked), a <table> whose second column carries style="text-align:center", a paragraph with <s>old</s> <strong>new</strong> and a working link, and the script tag and the bad link as escaped, harmless text. Untick the GitHub option and the same input shows the strict CommonMark result: the table and strikethrough become plain text and the checkboxes become literal [x].

Where converters differ

Markdown has one specification but many renderers. Differences you may see elsewhere: the original Markdown.pl and some CMS plugins treat a single newline differently (tick the line-break option to match GitHub comments); GitHub adds autolinks, footnotes, alerts and emoji shortcodes that are not part of this page; and renderers that allow raw HTML will output tags this page escapes. If your Markdown relies on raw HTML, this page is not the right tool: it would need a separate, trusted sanitiser that you control.

Sources: CommonMark 0.31.2 (spec.commonmark.org); GitHub Flavored Markdown spec (github.github.com/gfm); markdown-it (github.com/markdown-it/markdown-it), all as of 1 October 2026.