MD Browser - Markdown Viewer

View local Markdown files with a table of contents and Mermaid diagrams. Re-renders automatically when the file is saved.

MD Browser renders local Markdown files right in Chrome — with a table of contents, Mermaid diagrams, and live reload. Open any .md file from your computer (drag it into Chrome or open file:///…/README.md) and it is displayed as a clean, readable document instead of plain text. FEATURES • GitHub-style rendering: tables, task lists, autolinks, strikethrough, and syntax-highlighted code blocks (less common languages such as Dockerfile or PowerShell load on demand) • Sidebar table of contents that follows your scroll position; fold its sections, hide it or drag to resize • Sidebar listing the other Markdown files in the same folder and its subfolders, one click to open; also resizable, and folders you don't need can be hidden • Full-text search across the folder (Ctrl/⌘+Shift+F): matches grouped by file with the line, the heading and an excerpt; click one to jump there with the matches highlighted. Ignores case and character width; "This file" searches only the open document. No index, nothing stored • Quick file switcher (Ctrl/⌘+P): open any file of the folder by typing part of its name • The document's path from the folder root as a breadcrumb in the toolbar; click a folder to show it in the file sidebar • Favorites: star the documents you open often to keep them at the top of the file sidebar and first in the quick switcher • Mermaid diagrams (flowcharts, sequence diagrams, and more): click to enlarge, zoom and pan with the wheel or a drag, save as SVG or PNG • PlantUML diagrams, drawn inside the browser (the diagram source is never sent to a PlantUML server; the standard library can be fetched from a host you name in the settings, off by default); !include of local .puml / .iuml files from the document's folder and below • Math with KaTeX ($…$, $$…$$ and ```math blocks, as on GitHub), footnotes, and emoji shortcodes (:smile:) • Live reload: save the file in your editor and the page re-renders within about a second, keeping your scroll position • GitHub alerts (> [!NOTE], > [!WARNING] …) and collapsible front matter (YAML / TOML) • One-click copy button on code blocks, and a link button on headings • Switch to the raw Markdown source (button or Ctrl/⌘+Shift+M), with line numbers • Display settings: theme (system / light / dark), text size, content width, image and diagram size (50–200%), and fonts for body text and code • Custom CSS: style the document your own way from the settings panel; optionally, a folder's own .md-browser.css applies to the documents in it (off by default) • Resize a single image or diagram with the −/+ buttons that appear on hover; remembered for each document • Click an image to see it at full size, zoom and pan • Works from the keyboard and with screen readers: a skip link to the document, and Enter opens diagrams and images • Relative images and links to other .md files just work • GitHub's theme-specific images (#gh-dark-mode-only / #gh-light-mode-only, and <picture> with prefers-color-scheme) follow the chosen theme; printing uses the light version • Print-friendly output: prints (or saves as PDF) on white, without the toolbar and sidebars; options for paper size, margins, link URLs, a table of contents and page breaks before headings • Export: save the document as one self-contained HTML file (styles, diagrams and images embedded, in the current theme and size), or save it as PDF; options for a fixed light theme, a table of contents and embedded math fonts • Open in editor: a toolbar button opens the file in VS Code, Cursor or a custom URL scheme at the line you are reading (off by default) • Tab icon shows which tabs are rendered by MD Browser, and marks files that changed (or can't be read) while the tab was in the background • Built-in viewer (click the toolbar icon) to open files or whole folders, with a collapsible file tree and the folder name in the toolbar; a list of recently opened files and folders, and an adjustable scan limit for very large folders • Report a bug or suggest an idea from the settings panel: it opens a GitHub issue form, and nothing is sent unless you submit it PRIVACY Everything runs locally in your browser. No data is collected or sent anywhere, and there are no analytics. The extension only reads the Markdown file you are viewing and, for the file sidebar, the names of the files in that file's folder and below; their contents are read only when you search the folder, in the page and in memory only — nothing is indexed or saved. Saving a document as HTML reads the images it shows from that folder and its subfolders once, to embed them in the saved file; a PlantUML diagram's !include reads .puml files from there the same way, and, only if you switch it on in the display settings, a .md-browser.css in the document's folder or the root folder styles the document. SETUP (important) Chrome requires one extra step for extensions that read local files: 1. Open chrome://extensions and click "Details" on MD Browser 2. Turn on "Allow access to file URLs" The extension shows these steps automatically after installation. Open source (MIT): https://github.com/otaku1123/md-browser