MarkPad

A lightweight, cross-platform Markdown editor with live preview.

Edit Markdown on the left, see it rendered on the right — with a recent-files
sidebar, a formatting toolbar, JSON editing, light/dark theming, auto-save, and OS
file-association handling, in a small native Tauri app for Windows, Linux, and macOS.

Why • Features • Quick Start • Contributing • Architecture

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Why MarkPad?

Most Markdown editors ask for a tradeoff: a heavyweight Electron app that ships a whole browser to render a text file, a web app that wants your documents in the cloud, or a bare editor with no live preview at all.

MarkPad is the small, local-first alternative — a native desktop app that opens quickly, keeps every file on your machine, and shows your Markdown rendered side by side as you type. A recent-files sidebar, a one-click formatting toolbar, light/dark theming, optional auto-save, and real OS file-association handling make it usable day to day, without the bloat.

It is released under the MIT License and created by lezli01 at lezli01.is-a.dev. Contributions are welcome — see Contributing.

Features

Open a .md file and MarkPad treats editing and previewing as first-class, side-by-side work:

• Live split-pane preview. Edit Markdown in a line-numbered editor on the left, see it rendered on the right.
• Synced scrolling. In split view the panes follow each other — scroll either one and the other tracks the same part of the document, staying aligned even across tall images and long code blocks.
• In-document link navigation. Headings get anchor ids, so clicking an in-page link in the preview — like a table of contents [Section](#section) — smooth-scrolls to that heading within the preview pane.
• Formatting toolbar. One-click Markdown formatting from the editor header — bold, italic, strikethrough, inline code, headings, bullet/numbered lists, quotes, links, images, code blocks, tables, and horizontal rules — with shortcuts for the common ones (Ctrl/⌘+B, +I, +E, +K, and more). Buttons toggle the mark off when reapplied and light up to show the formatting at the cursor.
• Three view modes. Editor-only, preview-only, or side-by-side — switch at any time without losing the editor's content, selection, or undo history.
• JSON file support. Open a .json file (or switch any buffer with the pane-header language toggle) for syntax highlighting, live validation, line numbers, and collapse/expand of objects and arrays — plus one-click Format (2-space indent, Shift+Alt+F), Minify, and Sort keys. JSON documents are editor-only; the Markdown preview and format toolbar step aside while one is active.
• JSON typing comforts. In a JSON document the editor fills in the punctuation as you type: {, [ and " bring their closing partner, typing the closer steps over it, and Backspace between an empty pair removes both. Property names and string values get their quotes from the first character typed — true, false, null and numbers stay bare — and the separating comma appears with the first character of the next member, so a half-finished document is still valid JSON. Typing : at the end of a key steps out of the quotes, } and ] re-indent their line, and JSON pasted into an empty buffer is pretty-printed. Every automatic insertion undoes on its own with Ctrl+Z.

• Recent files sidebar. A left-hand panel lists up to 50 recently opened items — most-recent first, with modified files pinned to the top and marked. Click one to open it; modified and untitled documents keep their unsaved edits, cursor, and scroll position.
• Recents context menu. Right-click an entry for its full path, Copy full path, Copy file name, Reveal in file manager, and the bulk closes — Close, Close others, Close all above, Close all below, Close all saved, and Close all. Bulk closes skip anything with unsaved edits, so they never open a prompt and never lose a draft; each entry shows how many items it would close and greys out at zero.
• Collapsible, resizable sidebar. Drag the divider to resize the recents panel, or hide it entirely for distraction-free writing with the toolbar toggle or Ctrl+\; the width and collapsed state persist.
• New empty file. Start a fresh Markdown document from the toolbar or Ctrl+N / ⌘N; it appears in the recents list as an untitled draft, and the first Save prompts for a path.
• Light and dark theme. Honors the operating system's appearance preference by default, with a manual toggle in the toolbar.
• Open files from disk. Native file picker biased toward .md, .markdown, and .json, with a fallback to all files.
• Open files from your file manager. Set MarkPad as the default for .md or .json and a double-click opens MarkPad (or routes to the running instance).
• One window per user. MarkPad runs as a single instance; new file requests bring the existing window to the foreground.
• Save back to disk. Manual Save plus a visible modified indicator in the recents list so you always know whether your edits are on disk.
• Optional auto-save. Tick the box once and edits land on disk shortly after you stop typing, while a file is open.
• Unsaved-change guard. Closing an item only drops it from the recents list; the file on disk is untouched. Closing one that has unsaved edits prompts to Save, Discard, or Cancel so reflex clicks don't lose work.
• Resumes where you left off. Your recent-files list and the active document are restored on launch — including unsaved drafts and untitled documents, whose contents are saved locally so edits survive a restart. Files that have been moved or deleted are dropped when reopened.
• Persistent preferences. Theme, view mode, auto-save, and the sidebar's width and collapsed state are remembered between launches, stored locally.
• Responsive layout. Side-by-side on a normal window, stacks vertically at narrow widths.
• Safe preview. Rendered HTML is sanitized with DOMPurify before display.

Built With

• Tauri 2 — native desktop shell and filesystem access
• React 19 + TypeScript
• Vite — dev server and build
• CodeMirror 6 — editor
• markdown-it — Markdown rendering
• DOMPurify — preview sanitization
• Tailwind CSS — styling

For a high-level overview, see docs/architecture.md.

Quick Start

Prerequisites: Node.js LTS, npm, Rust + Cargo, and Tauri 2's platform prerequisites for your OS.

Install dependencies:

npm ci

Launch the desktop app:

npm run tauri dev

Or run just the frontend in a browser:

npm run dev

Development Checks

Frontend:

npm run lint
npm run build

Rust / Tauri (from src-tauri/):

cargo fmt --all --check
cargo clippy --all-targets --all-features -- -D warnings
cargo check --all-targets --all-features

Project Layout

src/             React + TypeScript UI (editor, preview, workspace, toolbar, recents panel)
src-tauri/       Rust crate that hosts the Tauri desktop runtime
specs/           Feature specifications (one folder per feature)
docs/            Architecture notes and supporting docs

Privacy

MarkPad is local-first. Files stay on your machine and the application does not send your content over the network. Preferences are stored in the local browser storage of the desktop runtime. Session state — your recent-files list, the active document, and any unsaved drafts — is stored locally in your platform's standard application-data directory; nothing is sent over the network.

Project Status

Early development, but already usable day-to-day. The split-pane workspace, the recent-files sidebar with draft persistence, file open/save, view modes, theming, auto-save, JSON editing with formatting and folding, OS file-association handling, single-instance routing, and session restore are working today. Specs for shipped and in-progress features live under specs/; open issues and follow-ups are in the issue tracker.

Contributing

Contributions of every size are welcome — bug reports, docs, new features, and test cases. MarkPad is spec-driven and intentionally contributor-friendly: every meaningful feature begins with a short spec under specs/ and clear acceptance criteria before implementation. Start here:

• Read the Contributing guide for development setup, the issue-to-PR workflow, and the checks expected before a pull request.
• Be a good neighbor: this project follows a Code of Conduct.
• Have a question or an idea? Open a Discussion.
• Found a bug or want a feature? Open an issue.

Releases are automated with release-please, so pull requests use Conventional Commits titles. Details are in CONTRIBUTING.md.

Security

MarkPad is local-first and sanitizes all rendered HTML before display, so its attack surface is small — but security reports are taken seriously. Please do not open a public issue for suspected vulnerabilities; report them privately via GitHub's private vulnerability reporting for this repository. See SECURITY.md for details.

License

MarkPad is released under the MIT License. © 2026 lezli01.