Markside: Markdown Viewer & Editor

Preview, edit, comment & share local Markdown. AI Review, GitHub-flavored, Mermaid, math, code highlighting, dark mode, PDF export.

Review beautifully rendered local Markdown files. Make quick direct edits without chat. Add inline comments like in Google Docs and send them to your agent. Share Markdown as a link your team can review instantly. Works with Claude Code, ChatGPT, Cursor, OpenClaw, and more. ❗ After installing, enable "Allow access to file URLs" in the extension details page. ❗ Supports local files only. Files on the web are not supported, yet. Free to use. No account required. Learn more at https://markside.app. 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, and common Markdown syntax • Extended syntax — Render task lists, footnotes, wikilinks, and linked URLs • Syntax highlighting — See highlighted code blocks for major languages • Mermaid diagrams — Render flowcharts, sequence diagrams, and more; zoom, pan, or expand them • Math formulas — Render inline and display math with KaTeX • YAML frontmatter — Display document metadata, including in SKILL.md files • GitHub alerts — Render Note, Tip, Important, Warning, and Caution callouts • Numbered headings — Optionally add section numbers without changing the file REVIEW • Inline comments — Select text and leave a comment, like commenting in a Google Doc • Quick comment presets — Instantly save a preset comment such as Clarify, Verify, or Condense • Review History — See a reviewer's comments alongside your own, each anchored to its passage • Agent-ready prompts — Copy any comment as a prompt for your coding agent WORK WITH YOUR CODING AGENT (BETA) Install the free Markside Agent Skill for Claude Code, Codex, Cursor, and other agents: npx skills add ericjy/markside --skill markside -g • Open from your agent — Run /markside to open the file your agent just wrote, without finding its path • Review loop — Run /markside review PLAN.md, comment in Markside, and click Send review to agent. The agent addresses each comment and replies until you finish the review • Interviews — Let your agent's questioning skill, such as /grill-me, ask its questions as cards in Markside. Pick an option or answer in your own words • Local by design — Comments travel through a file beside your document. No server, no account • Review loop and interviews require Node.js 20+. Learn more at https://markside.app/skill SHARE • Link Snapshot — Turn a saved local file into a readable link, with the content encoded in the URL and no upload • Hosted Snapshot — Encrypt saved Markdown in your browser and create a shorter link that expires in 30 days • Bring your review along — Optionally include your comments so feedback travels with the link • Reviewed Snapshots — Recipients can add their own feedback and share it back as a new link EDIT • In-place editing — Make quick changes without leaving Chrome • Three modes — Choose Preview, Source, or live Split view • Live preview — Edit beside a responsive rendered document • CodeMirror editor — Syntax highlighting, autocompletion, keyboard shortcuts, and undo history • Formatting toolbar — Insert tables, images, and links without remembering syntax • Emoji insert — Add common symbols to Markdown documents • Manual or Auto Save — Save with Cmd+S / Ctrl+S or enable Auto Save • Conflict protection — Review changes before overwriting a file modified on disk • Reload comparison — See additions and removals after reloading a Markdown file, and comment on removed passages NAVIGATE • Folder browsing — Open a local folder to explore your project • More than Markdown — Browse code, images, and other files in the tree • 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 open folder as you type • New Markdown file — Create a file in the open folder and start editing it in a new tab 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 • Source files — View supported text and code files directly in the editor • Image viewer — Open local images without leaving Markside • Theme toggle — Switch themes without reloading the page • Full width — Expand the document across the available browser space • Zen mode — Hide the toolbar, file tree, and outline to focus on the document • Word count — See word count and reading time at the top of Preview • Free access — Use every local feature with no account required WHAT'S NEW IN 1.7.0 • Review with your coding agent: send comments to your agent and see its replies (Beta) • Answer agent interviews in Markside with Question Cards (Beta) • Faster Mermaid diagrams that match your document's font and colors • Calmer reading: a narrower default page width, quieter styling, and Zen mode 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." 3. Open any .md file in Chrome. Markside renders it automatically. PRIVACY Markside is privacy-first. Local files and reviews stay in your local browser during ordinary use. A Link Snapshot carries its content in the URL and not uploaded to Markside server. If you explicitly create a Hosted Snapshot, Markside extension encrypts it locally before upload, so Markside server stores ciphertext only. The decryption key stays in the URL fragment and not visible to Markside server. Directory and file handles are stored in your browser's IndexedDB. No analytics or telemetry. COMPATIBILITY Chrome and Chromium-based browsers such as Edge, Brave, and Arc are supported. Firefox and Safari are not supported.