Markside — Markdown Viewer and Editor

Render and edit Markdown in your browser. Fast. Private. Delightful. File tree, outline, quick switcher, syntax highlight, Mermaid.

Markside lets you review and edit your local markdown files right inside your browser. Drag a markdown file to your browser and it renders instantly and beautifully. Make surgical edits in place without LLM roundtrips and token cost. Work inside your browser without resorting to a Markdown app or an IDE. Work with Claude Code, Codex, Cursor, or any tool that writes markdown. Everything stays local. Completely free to use. No account required. READ • Instant rendering — Open a Markdown file and it renders immediately • Document outline — Browse an automatically generated right-side table of contents • Rich Markdown — Support headings, lists, tables, images, code, all common markdown • Extended syntax — Render task lists, footnotes, wikilinks, and linked URLs • Syntax highlighting — See beautiful code blocks for every major language • Mermaid diagrams — Render flowcharts, sequence diagrams, Gantt charts, and more • YAML frontmatter — Display document metadata; great for SKILL.md etc. • GitHub alerts — Render Note, Tip, Important, Warning, and Caution callouts EDIT • In-place editing — Make quick changes without LLM roundtrips • Three modes — Choose Preview, Source, or live Split view • Live preview — Edit beside a responsive rendered document • CodeMirror editor — Syntax highlighting, autocompletion, keyboard shortcuts, undo history, etc. • Formatting toolbar — Quick insert tables, images, links, etc. without remembering syntax • Emoji insert — Quick insert emoji like commonly used in .md docs • Manual or auto save — Save with Cmd+S / Ctrl+S or auto save with debounced • Conflict protection — Review changes before overwriting a file modified on disk NAVIGATE • Folder browsing — Open local folder to explore your whole project • All files — See every file type in the tree, not just Markdown • Quick switcher — Press Cmd+P / Ctrl+P to find a file in the open folder • Smart matching — Connect each local file to the right saved folder automatically • Relative links — Follow links between nearby local documents • Compact breadcrumbs — Browse the current file path without crowding the toolbar • Fuzzy search — Search across the entire folder as you type OTHER • PDF export — Create a clean, light-theme document through Chrome's Save to PDF workflow • CJK support — Export documents containing Chinese, Japanese, and Korean text correctly • Source files — View supported text and code files directly in the editor • Image viewer — Open local images without leaving Markside • Theme toggle — Switch themes instantly without reloading the page • Full width — Expand the document across the available browser space • Free access — Use every local feature with no account required WHAT'S NEW IN 1.1.0 • Split view — Edit beside a responsive live preview • PDF export — Create polished documents, including files with CJK text • Folder matching — Reopen the right saved folder automatically for each local file • GitHub alerts — Render Note, Tip, Important, Warning, and Caution callouts • Interface polish — Use refined editor controls, file actions, sidebars, and print layouts SET UP IN 30 SECONDS 1. Install Markside from the Chrome Web Store. It's free, with no account required. 2. In extension settings, enable “Allow access to file URLs.” One toggle. 3. Open any .md file in Chrome. Markside takes over automatically. PRIVACY Your files stay local. Everything is read directly in Chrome. Markside does not upload file contents, paths, or folder structure. Markside collects no analytics or telemetry. Directory and file handles are stored only in your browser's IndexedDB. COMPATIBILITY Chrome and Chromium-based browsers such as Edge, Brave, and Arc are supported. Firefox and Safari are not supported.