From Markdown to HTML
Markdown is a plain-text formatting syntax created by John Gruber in 2004 and later pinned down by the CommonMark specification. It lets you write structured documents — headings, lists, links, code — without the noise of raw HTML tags, then convert them to clean markup whenever you need it.
A parser turns your text into HTML in two steps. First it tokenizes the source, recognising markers like # for headings, * for emphasis, and triple backticks for code fences, and builds a tree of nodes from them. Then it walks that tree and emits the matching semantic HTML — <h1>, <strong>, <pre><code>, and so on. This preview uses a CommonMark + GitHub Flavored Markdown parser, so tables and task lists render the same way they do on GitHub.
Everything runs 100% in your browser. Your drafts are parsed and rendered locally and never sent to a server, which keeps unpublished docs and internal notes private.
Markdown vs. WYSIWYG vs. raw HTML
Plain text with light markup — keyboard-only, diff-friendly, future-proof.
Rich editors or hand-written HTML give full control at the cost of portability.
Where developers use it
Polishing a README
Draft repository docs and setup guides, checking tables and code blocks render cleanly before you push.
Writing blog posts
Pre-write articles for Hugo, Astro, or Gatsby and confirm the formatting before dropping them into frontmatter.
API & wiki notes
Lay out endpoint examples and response samples in Markdown for an internal wiki or changelog.
Frequently asked questions
Yes. On top of standard CommonMark, it renders the GFM extensions you use most: tables, task lists, strikethrough, fenced code blocks, and autolinks. Single line breaks are honored too, so the preview matches what you'd see on GitHub.
The parser runs in two passes: it tokenizes the source into block- and inline-level nodes (headings, lists, emphasis, code fences), building an abstract syntax tree, then renders that tree to semantic HTML. Doing it as a tree — rather than naive find-and-replace — is what makes nesting like lists-inside-blockquotes render correctly.
Yes — switch the right panel to HTML to see the rendered source, or hit Copy HTML from either view to grab clean, semantic markup (<h1>, <ul>, <pre><code>, …) ready to paste into a CMS or template.
Markdown is the original 2004 syntax by John Gruber; CommonMark is a strict, unambiguous specification of it, so every compliant parser produces the same output. GFM is CommonMark plus GitHub's extensions. This tool follows CommonMark + GFM.
Markdown lets you drop in raw HTML, which is convenient but is the usual source of XSS when you render other people's input. Here you're previewing your own text locally, so it's fine — but if you render user-submitted Markdown in production, always sanitize the output (e.g. with DOMPurify) before inserting it.
No. Parsing and rendering happen entirely in your browser, so READMEs, release notes, and unpublished drafts never leave the page.