Markdown Previewer

Render local markdown files beautifully — GFM, Mermaid diagrams, syntax highlighting, TOC sidebar, dark mode, and more.

A Chrome (and Chromium derivatives) extension that renders local `.md` files beautifully — right in the browser. Open any markdown file via `file://` protocol and get GitHub-style rendering with a navigable outline, Mermaid diagrams, syntax highlighting, interactive checkboxes, and dark mode. MARKDOWN RENDER ENGINE Full GitHub Flavored Markdown support powered by markdown-it, plus: - Syntax-highlighted code blocks - 20+ languages with automatic detection, language labels, and one-click copy - Mermaid diagrams - flowcharts, sequence diagrams, Gantt charts, and more rendered inline as SVG - Math / LaTeX - KaTeX rendering for inline and block equations - Task lists - interactive checkboxes you can toggle and save (see below) - Tables - full GFM tables with colspan, rowspan, and multi-line cell support - Footnotes - numbered references with back-links - GitHub-style alerts - `[!NOTE]`, `[!TIP]`, `[!IMPORTANT]`, `[!WARNING]`, `[!CAUTION]` - Emoji shortcodes - `:rocket:` becomes :rocket: - Subscript / Superscript - `H~2~O` and `x^2^` - Highlighted text - `==marked==` - Definition lists - term/definition pairs INTERACTIVE CHECKBOXES Click a checkbox in the rendered preview to toggle it. A floating save bar appears so you can download the updated file with your changes preserved. No editor needed. SIDEBAR OUTLINE A collapsible sidebar shows the full heading hierarchy of the document: - Hierarchical tree with collapsible sections - Fuzzy search to filter headings instantly - Scroll spy highlights the current section as you read - Keyboard navigation through search results HOW IT WORKS The extension injects a content script into `file://` URLs matching `.md` and `.markdown` extensions. It reads the raw text content, parses it through markdown-it with all configured plugins, and replaces the page with the rendered output — styled, themed, and ready to read. Settings and preferences are stored in `chrome.storage.sync`, so they follow you across devices where you're signed into Chrome. PERMISSIONS - Storage - persist theme, plugin settings, and UI preferences - Downloads - save modified files when checkboxes are toggled BUILT WITH - WXT (https://wxt.dev/) — Vite-based browser extension framework - markdown-it (https://github.com/markdown-it/markdown-it) — Markdown parser - highlight.js (https://highlightjs.org/) — Syntax highlighting - Mermaid (https://mermaid.js.org/) — Diagram rendering - KaTeX (https://katex.org/) — Math typesetting