acento.io
Text utility

Markdown Preview

Render Markdown to HTML live in a split-view editor — your content never leaves your browser.

By Carlos Suárez , Systems engineer
Last updated:

What this Markdown preview does

This English-language Markdown renderer gives you an instant, side-by-side view of your source and the rendered output — no build step, no install, no account. Paste or type GitHub-flavored Markdown and the preview updates as you type. When you're ready, switch to the HTML tab to copy the raw markup, or hit Download .html to get a self-contained file you can attach to an email, drop into a docs folder, or open straight in a browser. Because the tool is 100% client-side — your data never leaves your browser, no uploads, no tracking, no server logs — it's safe to use with confidential drafts, NDA documents, or internal specs you'd rather not send to a third-party server. If you also need to clean up encoding issues in the output, the [HTML entities encoder/decoder](/en/html-entities/) handles that without leaving the tab.

Features

  • Live split-view editor. Source and rendered preview sit side by side and stay in sync as you type — no refresh needed.
  • GitHub-flavored Markdown support. Tables, fenced code blocks, strikethrough, and task lists all render correctly. GFM is the de-facto standard for README files and most static-site generators, so what you see here matches what GitHub shows.
  • Raw HTML output tab. Switch to the HTML view to inspect or copy the generated markup. Useful when you need to paste into a CMS, an email template, or a legacy system that expects HTML rather than Markdown.
  • One-click .html download. Exports a complete, self-contained HTML file with a proper doctype and UTF-8 charset declaration — ready to open in any browser or share as an attachment.
  • Preview-only mode. Hide the editor to read the rendered document without distractions — handy for a final proof before publishing.
  • Zero-dependency privacy. Everything runs locally in your browser. No content is sent to any server, which makes this tool appropriate for confidential or legally sensitive documents.

How to use the Markdown preview

Open the tool, type or paste your Markdown, and the preview updates instantly on the right.

  1. Paste or type your Markdown. Click the editor on the left and start typing, or paste existing content. GFM syntax like **bold**, # Heading, - [ ] task, and fenced code blocks with triple backticks all work out of the box.
  2. Check the live preview. The right pane renders in real time. Use this to catch formatting mistakes — a missing blank line before a list or an unclosed code fence — before committing or publishing.
  3. Inspect the HTML if needed. Click the HTML tab to see the generated markup. You can copy individual tags or the full output to paste into another system.
  4. Download the finished file. Click Download .html to save a complete HTML document. The file includes a <meta charset="UTF-8"> declaration and a viewport tag so it displays correctly on mobile.
  5. Switch to preview-only for proofreading. Click Preview to hide the editor and read the rendered document at full width before you ship it.

Common use cases

  • Previewing GitHub READMEs before committing. Many developers in Austin and New York write README files locally but only discover rendering issues after pushing. Use this markdown live preview to catch broken tables or misaligned headings before the commit.
  • Converting Markdown to HTML for email distribution. Download the .html file and attach it to an internal email or drop it into a shared drive — recipients get a clean, readable document without needing a Markdown viewer.
  • Drafting blog posts for static-site generators. If you write content for Jekyll, Hugo, or Astro, you can proof your Markdown here before running the build. Note that YAML frontmatter is not rendered — this tool focuses on the body content.
  • Teaching Markdown syntax. The split-view layout gives instant feedback, making this a practical tool for onboarding teammates or students who are learning Markdown for the first time.
  • Working with confidential drafts. Legal documents, NDAs, and internal specs often can't be uploaded to cloud services. Because this is a fully client-side markdown renderer, nothing leaves the machine — suitable for sensitive content.

Frequently asked questions

Does this tool send my Markdown to a server?

No. The entire rendering pipeline runs in your browser using JavaScript. Your content is never uploaded, logged, or processed on any server. This makes it safe to use with confidential or legally restricted documents.

What Markdown flavor does this renderer support?

It supports GitHub-Flavored Markdown (GFM), which extends the original CommonMark spec with tables, fenced code blocks, strikethrough, and task lists. GFM is the flavor used by GitHub, GitLab, and most static-site generators. If you paste input written for MultiMarkdown or Pandoc extensions, some features may not render as expected — the flavors differ in subtle ways, especially around nested lists and raw HTML escaping.

Why doesn't syntax highlighting work in code blocks?

Adding a syntax highlighter like Prism or highlight.js would significantly increase the bundle size. This tool keeps things lightweight and fast by intentionally omitting it. The code still renders in a monospace block — it just won't be colorized.

Is this different from the VS Code Markdown preview?

Functionally similar — both render GFM live. The VS Code markdown preview is built into the editor and is great when you're already in VS Code. This tool is browser-based, so it works on any device without an install, and it adds an HTML export option that VS Code doesn't offer natively. If you use Neovim or Sublime Text, editor-native markdown preview plugins exist for those too, but again require setup.

Can I use raw HTML inside my Markdown?

Yes, mixing HTML inside Markdown is valid in GFM. For example, you can use <details> and <summary> tags for collapsible sections. Keep in mind that how parsers handle this varies — some sanitize certain tags. If you need to encode special characters in the output, the [HTML entities encoder/decoder](/en/html-entities/) can help. You can also use MDN — encodeURIComponent as a reference for URL-encoding strings that appear in your HTML attributes.

Does this support Mermaid diagrams or YAML frontmatter?

No. Mermaid diagram rendering requires a separate library that would significantly increase load time, and YAML frontmatter is a convention used by static-site generators — not part of GFM itself. This tool focuses on body content rendering and honest scope: it does one thing well rather than approximating many things poorly. For text transformations alongside your Markdown work, the [text diff](/en/text-diff/) tool can help you compare two versions of a document.