Write, edit, and preview GitHub Flavored Markdown (GFM) in real time. Features LaTeX math typesetting ($x^2$), code syntax highlighting, document outline, and styled HTML export—100% in-browser and private.
In 2004, John Gruber and Aaron Swartz conceived Markdown with a single, uncompromising design philosophy: a Markdown-formatted document should be publishable substantially as-is, as plain text, without looking like it has been marked up with formatting tags. Before Markdown, writing for the web meant constantly interrupting one's train of thought to construct nested HTML tags like <p>, <strong>, and <ul><li>. Gruber realized that email writers had already invented intuitive formatting idioms over decades—such as surrounding words with *asterisks* for emphasis or prefixing lines with > to quote someone.
As Markdown exploded in popularity, dozens of divergent implementations appeared (PHP Markdown Extra, MultiMarkdown, Pandoc, and Maruku), each interpreting ambiguous edge cases differently. To resolve these fragmentation problems, standard bodies and developer platforms established formal specifications:
Created by John Gruber as a Perl script (Markdown.pl). It introduced the baseline syntax: ATX headings, inline links, blockquotes, code spans, and unordered lists.
Spearheaded by Jeff Atwood and John MacFarlane to produce a mathematically unambiguous, formally tested specification that parses consistently across C, Python, JavaScript, and Rust.
GitHub's official extension of CommonMark. Adds practical developer features: pipe tables, task checklists, strikethrough, autolinks, and fenced code blocks with language identifiers.
Below is a comprehensive reference covering standard CommonMark, GitHub Flavored Markdown (GFM), and scientific LaTeX extensions:
| Element | Markdown Source Syntax | Rendered Behavior & Purpose |
|---|---|---|
| ATX Headings 1 – 3 | # H1 ## H2 ### H3 | Generates semantic <h1>, <h2>, <h3> tags with auto-generated anchor IDs for document outlines. |
| Bold & Emphasis | **Bold** and *Italic* | Applies strong visual emphasis (<strong>) and stress emphasis (<em>). |
| GFM Strikethrough | ~~Deleted sentence~~ | Wraps in <del> tag to indicate deprecated APIs or completed requirements. |
| Blockquote Callout | > Critical alert note | Renders styled <blockquote> with accent border for notes, tips, and warnings. |
| Interactive Task List | - [x] Done - [ ] Pending | GFM checklist with native disabled checkbox elements for progress tracking. |
| GFM Aligned Table | | Item | Cost | | :--- | ---: | |
Pipe-delimited table with colon colons for left, center, and right alignments. |
| Fenced Code Block | ```python def hello(): pass ``` |
Pre-formatted code block with syntax highlighting and dynamic copy-to-clipboard button. |
| LaTeX Math Formulas | $E=mc^2$ $$ \int e^x dx $$ | Instant client-side mathematical typesetting via KaTeX with zero cloud roundtrips. |
Technical documentation, machine learning research papers, and academic notes frequently require complex mathematical formulas. Our viewer integrates KaTeX, the fastest web math typesetting engine developed by Khan Academy, providing synchronous rendering without layout jumps:
Wrap mathematical formulas in single dollar signs to keep them inline with prose: $f(x) = \sigma(w^T x + b)$ renders seamlessly within sentences without disrupting paragraph line-height.
Wrap formulas in double dollar signs on separate lines to render centered equations: $$\int_{-\infty}^\infty e^{-x^2} dx = \sqrt{\pi}$$ with full support for integrals, matrices, fractions, and Greek symbols.
Markdown has evolved into the universal interchange standard for Large Language Models (ChatGPT, Claude, Gemini), personal knowledge management tools (Obsidian, Logseq, Foam), and modern developer platforms. Here is why technical teams standardize on Markdown:
Large Language Models are billed per token. When passing tabular data or documentation into model context windows, HTML or JSON dictionaries repeat closing tags and keys on every row. A GFM pipe table conveys identical relational schema while consuming up to 75% fewer tokens, allowing you to include 4x more data inside prompt budgets.
Binary formats (like Microsoft Word .docx or Apple Pages) produce unreadable binary diffs when committed to Git. Markdown files are plain text, enabling line-by-line diff tracking, pull request code reviews, automated linting via markdownlint, and conflict resolution.
Writing in Markdown ensures that your knowledge repository remains independent of any software vendor. If a note-taking application changes its pricing or shuts down, your raw .md files remain 100% readable, searchable, and convertible on any operating system.
Markdown parsers operate in two main phases: (1) Lexing raw text into an Abstract Syntax Tree (AST) of tokens, and (2) Compiling the AST into semantic HTML. Because Markdown specifications intentionally allow raw HTML passthrough (like <div> or <iframe>), untrusted Markdown can introduce Cross-Site Scripting (XSS) vulnerabilities if rendered directly.
Our viewer protects user security by piping all generated HTML through DOMPurify, neutralizing malicious <script>, onload, and onerror payloads while preserving valid typography, MathML, and SVG icons.
If you are automating documentation builds, processing user input, or building automated report pipelines, here is how to parse Markdown in Python, JavaScript/Node.js, and CLI:
import markdown
raw_markdown = """
# Engineering Spec
| Service | Status | Latency |
| :--- | :---: | ---: |
| Auth API | Active | 12ms |
"""
html_output = markdown.markdown(
raw_markdown,
extensions=['tables', 'fenced_code', 'codehilite', 'toc']
)
print(html_output)import { marked } from 'marked';
import DOMPurify from 'dompurify';
const rawMarkdown = "## Release Notes\n- [x] Snappy decompression\n- [ ] Multi-sheet export";
const cleanHtml = DOMPurify.sanitize(marked.parse(rawMarkdown));
document.getElementById('content').innerHTML = cleanHtml;# Convert Markdown to standalone styled HTML
pandoc README.md -s -o documentation.html --highlight-style=tango
# Convert Markdown to PDF via wkhtmltopdf or LaTeX
pandoc report.md -o report.pdf --pdf-engine=xelatexMarkdown is a lightweight, human-readable plain text formatting syntax created by John Gruber in 2004. It allows writers and developers to format headings, lists, bold text, code blocks, and links using simple punctuation characters without writing complex HTML tags. It is universally supported across GitHub, GitLab, Notion, Obsidian, static site generators (Docusaurus, Jekyll, Hugo), and AI workflows.
Yes, 100%. All Markdown parsing, LaTeX math equation typesetting (via KaTeX), syntax highlighting, and HTML rendering occur entirely within your browser's local client-side memory. No documents, notes, code snippets, or sensitive text are ever transmitted to or stored on any external server.
CommonMark is a standardized, unambiguous specification of the original Markdown syntax created to eliminate parsing inconsistencies across platforms. GitHub Flavored Markdown (GFM) is a formal extension of CommonMark that adds support for practical developer features including tables, task completion checklists, strikethrough, autolinks, and fenced code blocks with language identifiers. Our Markdown viewer fully supports both CommonMark and the complete GFM specification.
Yes. You can render mathematical formulas and scientific notation using standard TeX/LaTeX delimiters. Use single dollar signs $E = mc^2$ for inline formulas, or double dollar signs $$\frac{-b \pm \sqrt{b^2 - 4ac}}{2a}$$ for centered block equations. The formulas are processed client-side via KaTeX for instantaneous rendering.
You can export your document in multiple ways using the toolbar: (1) Copy the raw Markdown text, (2) Copy the sanitized rendered HTML code, (3) Download a .md file, or (4) Download a standalone, responsive, styled .html file ready for web publishing.
Yes. You can switch between Visual Preview and Markdown Code views. You can also click the Fullscreen icon to expand the workspace to full viewport size without distraction, and press the Escape (Esc) key or click 'Back to Normal View' at any time to return.