Markdown Preview is a free, browser-based tool that renders Markdown into formatted HTML as you type. You write in plain-text Markdown on one side and see the finished, styled result on the other - headings become real headings, - item becomes a bullet list, **bold** becomes bold, and a fenced code block becomes a monospaced, formatted block.

Markdown is the lightweight markup language behind README files, GitHub comments, wikis, static-site posts, chat messages and note apps. It is designed to be readable as plain text, but the whole point is that it gets rendered somewhere - and small syntax mistakes that look fine in the source can produce broken output. A live preview closes that gap: you see the rendered version immediately, so there is no guessing and no commit-then-check loop.

Everything happens on this page. You paste Markdown in, you see HTML out, and your text stays with you - nothing is uploaded to a server or stored after you leave.

The usual way to check Markdown is to publish it and look - push the README, refresh the GitHub page, or rebuild the site - then go back and fix whatever came out wrong. That round trip is slow, and it puts half-finished formatting in front of other people.

An online preview gives you the rendered result without any of that. You do not need to install an editor, configure a Markdown plugin, or run a local build just to confirm a table lines up or a nested list indents correctly. It works the same on any operating system and on mobile, so you can check a snippet anywhere.

Privacy matters here too, because Markdown is often internal - unpublished release notes, private documentation, draft posts, meeting notes. Dev Nexus runs the parser entirely in your browser, so your text is never sent to a third-party server, logged or retained. That makes it safe for sensitive drafts, and it keeps the preview instant because there is no network round trip on every keystroke.

Using the tool takes three moves. First, paste or type your Markdown into the editor - a README, a batch of notes, a single paragraph or a long document all work. Second, read the live preview beside it: as you type, the rendered version updates so you can confirm headings, lists, links, tables and code all come out the way you meant. Third, copy what you need - your tidied Markdown source, or the generated HTML from the HTML view.

A few habits make this smoother. Keep a blank line between block elements - paragraphs, lists, headings and code fences - because Markdown uses blank lines to separate them, and missing ones are the most common cause of "why didn't this render?" Use the preview to sanity-check anything structural, especially tables and nested lists, where a single misplaced space changes the output. And when you want the finished markup rather than the source, switch to the HTML view and copy from there.

A Markdown preview is useful anywhere Markdown gets written before it gets published:

• README and docs: check that your project's README renders cleanly - badges, headings, code blocks and tables - before you commit it.
• GitHub and GitLab comments: preview an issue, PR description or comment so your checklists, links and code blocks come out right the first time.
• Static-site and blog posts: draft a post in Markdown and confirm the formatting before running your site build.
• Notes and documentation tools: verify how Markdown will look in apps like Notion, Obsidian or a wiki.
• Learning Markdown: type a snippet and immediately see what each piece of syntax does - the fastest way to learn.
• Converting to HTML: render Markdown and grab the generated HTML to paste into an email, a CMS or a page.

When you want to check how the rendered HTML behaves as a real page, open the HTML Preview tool. And when you need to know how long a piece of writing is, run it through the Word Counter.

Get cleaner Markdown with a few simple rules:

• Separate blocks with blank lines. A list, heading, blockquote or code fence needs a blank line before and after it. Cramming a list directly under a paragraph is the number-one reason it renders as one run-on line.
• Close your code fences. Every opening `` needs a matching closing ``. An unclosed fence swallows the rest of your document into a code block - the preview makes this obvious instantly.
• Watch table pipes and the divider row. A GitHub-style table needs the |---|---| separator line under the header. Use colons in it (:---, :---:, ---:) to control column alignment.
• Indent nested lists consistently. Use the same indentation (two or four spaces) for each level so sub-items nest correctly rather than flattening.
• Remember raw HTML may be escaped. For safety, many previewers show raw HTML as text rather than executing it. If a tag "doesn't work," that is usually why - stick to Markdown syntax where you can.