Your agents write Markdown. You read it in Mark.

A native Mac editor for plans, specs and reports. Diagrams and tables render inline; agent edits reload live.

Download for Mac

v2.1 beta Apple Silicon, 11 MB

One file, two authors.

Your agent drafts, you correct, and the file on disk carries the conversation. Nothing to paste back into a chat.

  1. The agent writes

    It saves plan.md and opens it with open -a Mark.

  2. You edit in place

    Delete a step, rewrite a paragraph, leave a note under a table. Save.

  3. The agent reads the diff

    Its next write reloads in Mark without moving your cursor.

Teach your agent once

Paste into CLAUDE.md, AGENTS.md or any system prompt your agent reads.

When you produce a plan, spec, report, or any document longer
than ~50 lines, write it to a .md file and open it for the user:

    open -a Mark <file>.md

The user reads and edits it in Mark, which reloads the file when
it changes on disk. When the file changes, read the new version:
the user left corrections inline. Treat the diff as your next
instruction.

113 MB with 25 documents open.

We opened the same 25 files in four editors and counted every process each one owns. Mark renders with the WebKit already on your Mac instead of shipping its own browser engine.

RAM with 25 documents open, all app processes

  • Agentic AI IDE A********** · Electron
    2,313 MB
  • General code editor V* C*** · Electron
    1,517 MB
  • Note-taking editor O******* · Electron
    803 MB
  • Mark Native · system WebKit
    113 MB

Method: Apple M5, 32 GB, macOS 26.6, 21 September 2026. The same 25 Markdown files (about 54 KB) in every editor; Electron apps ran in fresh profiles, and RAM is the sum of all app-owned processes after a 25-second settle. Mark v2.1.11 downloads at 11.7 MB and idles near 61 MB with one file open. Competitor names are masked on purpose; the pattern is the point. Reproduce it with tools/benchmark/editors-bench.sh.

Everything an agent puts in a .md file.

Rendered in place, in one pane. No split preview, no export step.

Mark showing a formatted document with headings, emphasis, lists and a quote
Headings, lists, quotes and inline code, edited where they are rendered. Switch to source mode when you want the raw text.
Fenced code blocks with syntax highlighting in Mark
Fenced code with highlighting for more than 60 languages.
A Mermaid architecture flowchart and a pie chart rendered inline
Mermaid v11 flowcharts, sequence diagrams and Vega charts render inline and follow the theme.
KaTeX equations rendered inline in a document
KaTeX for inline and display equations.
A project dashboard built from Markdown tables
Tables render as tables and edit cell by cell.
A roadmap with checked and unchecked task lists
Task lists you can tick off while the agent works through them.

A small app with the right parts.

For the agent loop

Live reload
External edits appear as they land. Run mark --watch plan.md from any script.
Inline diff
⌘D compares against git HEAD or a .before file, so you see exactly what the agent changed.
Unsaved work stays safe
A reload never overwrites a tab you are still editing; you choose to save, discard or keep it.

For reading

33 themes and custom CSS
Light, dark and everything between, synced across windows.
Preview mode
Double-click a .md file in Finder and it opens read-only. Make Mark the default handler if you like.
Folders and search
A sidebar file tree, tabs, and find across a whole folder.

For your Mac

Native, not Electron
Tauri and the system WebKit view, a real menu bar, system spell-check, proper shortcuts.
Signed and notarized
Developer ID signed, notarized by Apple, updated through Homebrew.

For your files

No account, no telemetry
Nothing leaves your machine. Files stay plain Markdown on disk.
Open source
MIT licensed, built on the Muya engine from Mark Text. Read the code on GitHub.

Install in one line.

Homebrew keeps Mark updated. Paste this into Terminal.

Download the .dmg (11 MB) Read the quick start Build from source
Apple Silicon macOS 12 or later Intel Macs: build from source Mac App Store version on the way