A free Markdown viewer for Mac.
Open and preview .md files as clean documents. Add a comment to any phrase and the note stays inside the file, invisible everywhere else.
macOS 14+ · 5.8 MB
Markdown you can argue with.
Your agent writes.
You answer in the margin.
Imark ships a review skill for Claude Code and Codex. The agent opens its Markdown plan and waits; you comment on exact phrases, then approve or request changes. The notes stay in the file, with no review server or separate account.
Claude Code or Codex opens its plan in Imark and waits.
You read it as a document and mark it up.
Approve, or request changes.
It reads your notes back and carries on.
Space bar. No app to open first.
A Quick Look extension renders the file in place, with the same typography, code highlighting and diagrams as the app itself.
Everything you expected
it to already do.
Keep your editor where it is
Write in Cursor, VS Code, Zed, anything. Imark follows every save and keeps your scroll position, so you can leave it open on the other half of the screen and stop switching windows.
Never lose the thread
The outline folds itself on long documents and follows you as you scroll.
Diagrams and maths
Mermaid and KaTeX are bundled in. They work on a plane.
One window
Tabs, find, print to PDF with the comments included.
Nothing of yours leaves the machine
Documents render offline, every remote request blocked. The one network call, an optional daily check for new versions, carries a version number and nothing else.
Yours as much as mine.
MIT licensed, and the whole thing is about 5,000 lines of Swift you can read in an afternoon. Issues get answered. If it breaks one of your files I want to hear about it before anything else.
A star is how I find out anyone is using this
Issues are read the same day. Broken files come first.
Start with the job you need to do.
Open a file, preview it in Finder, read technical Markdown, or add a human review gate to Claude Code and Codex. Each guide gives you the direct path.
The ones people actually ask.
Select a markdown file in Finder, press ⌘I, choose Imark under “Open with”, and click “Change All…”. Imark registers as an alternate handler, so it never takes the association without being asked.
Your notes travel with the file.
Select a phrase, write what you think, and it is saved into the document as an HTML comment. Send the file to someone, open it on another machine, commit it. The note is still there, and no other app shows it.
The deadline is generous but achievable. <!-- imark quote="generous but achievable" by="miguel" at="2026-08-02T14:31Z" Achievable with which team? -->