Markdown Preview: Live-Preview Markdown as Rendered HTML
Write Markdown in the left pane and see the rendered HTML output instantly on the right. Supports GFM, tables, code blocks, and inline HTML.
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Markdown has become the universal plain-text format for documentation, README files, blog posts, wikis, and developer notes. Its syntax is lightweight and human-readable in raw form, but the rendered output — with formatted headings, bold text, tables, code blocks, and embedded images — is what most readers actually see. Working with Markdown without immediate visual feedback means constantly switching between an editor and a browser to check how your formatting looks.
This Markdown preview tool provides a split-pane interface where your raw Markdown source on the left renders instantly as styled HTML on the right. Every keystroke updates the preview in real time, so you can write and format confidently without any guesswork. It supports GitHub Flavored Markdown (GFM), which adds tables, task lists, strikethrough text, and fenced code blocks with syntax highlighting on top of the CommonMark baseline.
The tool is especially useful when drafting README files, writing documentation for open-source projects, composing content for a static site generator, or preparing formatted notes. Because rendering happens entirely in the browser, your content stays private and the tool is available offline after the initial page load.
What Is Markdown?
Markdown is a lightweight markup language created by John Gruber in 2004 with the goal of making plain text readable as-is while also being convertible to valid HTML. Its syntax uses punctuation characters as formatting cues: pound signs for headings, asterisks or underscores for bold and italic text, hyphens or numbers for lists, backticks for inline code, and triple backticks for fenced code blocks.
Over the years, Markdown has grown beyond Gruber's original specification. The CommonMark project established a rigorous, unambiguous specification, and GitHub extended it further with GitHub Flavored Markdown (GFM), which added tables, task checkboxes, strikethrough, and autolinked URLs. Most documentation tools, static site generators, and developer platforms today support GFM or a close variant.
Because Markdown compiles to HTML, it integrates naturally into web workflows. Blog platforms like Jekyll, Hugo, Gatsby, and Astro accept Markdown files directly as content sources. Documentation tools like MkDocs, Docusaurus, and VitePress use it as their primary authoring format.
How to Use This Tool
The preview tool is a simple two-pane editor with a live output panel. Here is how to get started:
- 1
Type or paste your Markdown
Click inside the left editor pane and type your Markdown source, or paste existing content from a README, blog post draft, or documentation file.
- 2
Watch the live preview
The right panel updates instantly with every change, rendering headings, lists, tables, code blocks, links, and images exactly as they will appear in most Markdown viewers.
- 3
Use GFM extensions
Try fenced code blocks with language identifiers (```js), pipe-delimited tables, task list checkboxes (- [ ]), and ~~strikethrough~~ to take advantage of GitHub Flavored Markdown features.
- 4
Copy or export the HTML
When your Markdown is ready, copy the raw source to use in your project, or copy the rendered HTML output if you need to paste formatted content into a CMS or email client.
Common Use Cases
Markdown is used across the full software development lifecycle. These are the most common scenarios where live preview adds real value:
- Drafting and formatting README files for GitHub, GitLab, and Bitbucket repositories before committing
- Writing technical documentation for frameworks, APIs, and libraries using MkDocs, Docusaurus, or VitePress
- Composing blog posts for static site generators like Jekyll, Hugo, Gatsby, Astro, and Eleventy
- Creating well-formatted issue descriptions, pull request bodies, and GitHub wiki pages
- Writing study notes, project plans, and meeting notes in a portable, readable plain-text format
Tips and Best Practices
Good Markdown documents are both readable in raw form and beautifully rendered. These tips help you write cleaner, more portable Markdown:
- Use ATX-style headings (# H1, ## H2) rather than underline-style (===) for consistency and compatibility across all Markdown parsers.
- Always add a blank line before and after code blocks, lists, and headings. Many parsers require this whitespace to correctly distinguish block-level elements from inline text.
- Prefer fenced code blocks (triple backticks) over indented code blocks (four spaces). Fenced blocks support language identifiers for syntax highlighting and are unambiguous.
- Use reference-style links for long URLs to keep the source readable: define '[id]: https://example.com' at the bottom and reference it as '[link text][id]' in the body.
- Validate your rendered output against GitHub's own renderer if your Markdown will live in a repository, since GitHub applies its own post-processing (like sanitizing certain HTML tags).
Frequently Asked Questions
What is the difference between CommonMark and GitHub Flavored Markdown?
CommonMark is a strict, unambiguous specification of the original Markdown syntax that resolves many edge cases and inconsistencies in Gruber's original description. GitHub Flavored Markdown (GFM) is a superset of CommonMark that adds tables, task lists, strikethrough, autolinks, and disallowed HTML filtering. Most modern tools support GFM or CommonMark.
Can I use HTML inside Markdown?
Yes, most Markdown parsers allow raw HTML inline within the document. This is useful for elements Markdown does not natively support, like centered text, colored content, or custom div containers. However, many publishing platforms and security-conscious renderers sanitize or strip certain HTML tags.
How do I add syntax highlighting to code blocks?
Use a fenced code block with a language identifier immediately after the opening triple backticks, for example: ```javascript. The renderer applies syntax highlighting based on the language token. Supported languages vary by renderer but commonly include js, ts, python, bash, json, yaml, and many others.
Does the preview work offline?
Yes. After the page loads in your browser, all rendering happens locally in JavaScript. You can disconnect from the internet and continue using the preview tool without interruption, which is useful when working on flights or in environments with unreliable connectivity.
Can I preview Markdown with frontmatter (YAML headers)?
The preview panel renders Markdown content and will display frontmatter YAML as a code block or preformatted text rather than parsing it as metadata, since frontmatter is consumed by static site generators (not renderers). You can still write and edit frontmatter in the editor pane.
How do I create a table in Markdown?
Use pipe characters to separate columns and hyphens to create the header separator row: '| Column 1 | Column 2 |' followed by '| --- | --- |' and then data rows. GFM supports optional column alignment by adding colons to the separator: ':---' for left, ':---:' for center, '---:' for right alignment.
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