GitHub Flavored Markdown (GFM) extends standard Markdown with additional features used on GitHub. Additions include: tables (| Syntax | Description |), task lists (- [ ] Todo item), strikethrough (text), auto-linking URLs without brackets, syntax highlighting in code blocks (```javascript), username mentions (@user), issue references (#123). GFM also has different line break handling - single line breaks create
tags. Standard Markdown requires two spaces or double line break. This tool supports full GFM syntax including tables, task lists, and fenced code blocks with syntax highlighting.

Tables use pipes | and hyphens - to separate columns and create headers. Basic syntax: | Header 1 | Header 2 | then | --------- | --------- | for separator, then data rows | Cell 1 | Cell 2 |. Alignment: left (default), center (:---:), right (---:). Cells can contain inline formatting like bold, italic, code. Tables must have header row and separator. Minimum 3 hyphens per column. This tool renders tables with proper HTML formatting. Note: tables are GFM extension, not in original Markdown.

Use clear heading hierarchy (# for title, ## for sections, ### for subsections). Start with brief overview and table of contents. Use code blocks with language specification (```python) for syntax highlighting. Include examples for each concept. Use lists (- or 1.) for steps and bullet points. Add links to related documentation. Use tables for comparing options or specifications. Include badges for build status, version, license. Keep paragraphs short (3-4 sentences). Use bold for important terms first use, inline code for commands/variables. Test all code examples before publishing. This tool helps preview documentation exactly as it will appear.

Use triple backticks with language name for fenced code blocks. Example:javascript for JavaScript, python for Python, bash for shell commands. Alternatively, indent 4 spaces for code block without syntax highlighting. Inline code uses single backticks: variable or function(). Common languages: javascript, python, java, go, rust, sql, html, css, json, yaml, bash, typescript. GFM supports 100+ languages. Syntax highlighting makes code more readable and helps identify errors. This tool provides real-time syntax highlighting preview for all major programming languages.

Links: [link text](https://url.com) or [link text](https://url.com "Title"). Reference-style: [link text][ref] then [ref]: url at bottom. Images: ![alt text](https://example.com/image.png) - same as link but with ! prefix. Image with link: [![alt](https://example.com/img.png)](https://example.com). Relative paths work: [docs](./docs/file.md) or ![logo](./images/logo.png). Auto-linking (GFM): bare URLs become clickable automatically. Best practices: always include alt text for accessibility, use descriptive link text (not "click here"), use HTTPS for external links. This tool renders all link and image types with proper HTML output.

Task lists (GFM feature) create interactive checkboxes using - [ ] for unchecked, - [x] for checked. Example: - [ ] Write documentation, - [x] Review code, - [ ] Deploy to production. Tasks must start with hyphen and space, then brackets, then space, then text. Nesting works with indentation. On GitHub, clicking checkboxes updates the markdown source. Useful for: project TODOs, issue tracking, meeting notes, feature checklists. This tool renders task lists with proper checkbox styling. Note: checkboxes display-only in preview, editing requires changing [ ] to [x] in markdown source.

Most markdown tools export to HTML - click "Export" or "Download HTML". Markdown converts to semantic HTML5 (# becomes

, ** becomes , etc.). For PDF: export HTML first, then print to PDF (Ctrl/Cmd+P, save as PDF). Alternative: use Pandoc command-line tool (pandoc input.md -o output.pdf) with LaTeX. For styled PDFs, add CSS to HTML then convert. GitHub renders markdown as HTML automatically. Static site generators (Jekyll, Hugo) convert markdown to HTML websites. This tool allows HTML export with included CSS styling. Raw markdown also works for version control and plain text editors.