Markdown Previewer

Type or paste Markdown on the left, see the rendered output on the right, live. Covers the part of Markdown that actually gets used day to day — headings, bold/italic, lists, links, images, blockquotes, fenced code blocks — without needing an editor plugin or a full static site build just to check formatting before you paste something into a README or a PR description.

Why this doesn't render raw HTML pasted into the input

Real Markdown, by the original spec, lets raw HTML pass straight through untouched — type <div> in a `.md` file and most renderers will happily output an actual <div>. That's fine when you trust the source, and actively risky in a general-purpose browser tool where you might paste in a snippet you copied from somewhere you don't fully trust. This previewer escapes HTML in the input before applying any Markdown formatting, so a stray <script> tag in pasted content shows up as visible text in the preview instead of silently executing — the same reasoning that governs why user-generated content on any real website gets sanitized rather than rendered as trusted markup.

What's covered, and what isn't

This handles the CommonMark core that shows up in 95% of real usage: headings (# through ######), bold and italic, ordered and unordered lists, blockquotes, fenced code blocks, links and images, and horizontal rules. It doesn't attempt tables, nested lists, footnotes, or the fuller GitHub-Flavored Markdown extensions — if you need those specifically, a full CommonMark/GFM library is the right tool, but for checking "does this README section actually format the way I think it does" before you commit it, this covers the common case without any setup.

Why Markdown won as the default for developer-facing docs

It's readable as plain text even before rendering — a Markdown file makes sense to a human reading the raw source, unlike HTML or heavier markup formats, and that's exactly why it became the default for READMEs, PR descriptions, wikis, static site generators and chat platforms. The syntax is deliberately minimal precisely so writing documentation doesn't feel like writing HTML by hand.