Keymark
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version
0.3.0
channel
Founders Beta
runs on
macOS, Windows
ai
Keymark AI, optional, on-device

The Markdown reader that understands your documents.

Keymark is a private, local-first Markdown reader and editor for macOS and Windows. Read, edit and see what changed since you last read, right after a light download. Turn on Keymark AI whenever you want to ask questions with cited answers or let it propose edits. It runs 100% on your computer.

~19 MBDownload for macOS BetaWindows

v0.3.0 Founders Beta · ~19 MB · macOS 14+ on Apple Silicon

migration-plan.md

Keymark

2 sections changed since you last read

Migration plan

Move search to the new storage layer.

Steps

  • Done: Snapshot the current index
  • Run pnpm migrate --dry-run
  • Switch reads to the new layer

Rollback

NoteKeep the old index for 48 hours.

Owners

AreaOwner
SearchAna
StorageLuis

On this device · Keymark AI

Question: What changed since yesterday?

Two things changed. A dry run now comes before the switch , and the old index stays for 48 hours .

Sources StepsRollback

Request: Add a step to compare results before the switch.

Proposed edit migration-plan.md

  - [ ] Run `pnpm migrate --dry-run`
+ - [ ] Compare results on both layers
  - [ ] Switch reads to the new layer
Nothing changes until you apply it.
Fig. 0 The same file, raw and rendered, with Keymark AI answering on this computer. Hover a citation to see its source, or apply the proposed edit.

§1Read

Markdown that reads like a well-edited book.

Double-click any .md file and it opens in Read mode, with everything GitHub renders plus math and diagrams. No reformatting, no waiting, even for huge files.

Keymark in Read mode showing a GitHub Flavored Markdown document, with the Outline panel listing its headings. Keymark in Read mode showing a GitHub Flavored Markdown document, with the Outline panel listing its headings.
Fig. 1 Read mode, with the Outline panel following along.
  • Editorial typography. A comfortable line length, an outline that follows you and a reading progress bar. Long docs stop feeling like walls of text.
  • Instant, even when it’s huge. Big files open fast and stay responsive.1
  • Everything GitHub renders. Alerts, tables, task lists and footnotes look the way their authors intended.
  • Math and diagrams. KaTeX formulas and Mermaid diagrams render right in the document.
  • Code that’s easy to read. Shiki syntax highlighting for code blocks in hundreds of languages.
  • Four themes. Paper, Graphite, Sepia and Contrast. Pick the one that’s easiest on your eyes, day or night.
  • Made for the docs you actually read. READMEs, specs, runbooks and the plans your AI agents write. README.md AGENTS.md CLAUDE.md .markdown .mdx (view)

§2Keymark AI

AI when you want it. One click, once.

Keymark AI is an optional add-on you turn on inside the app: one click, a one-time download of ~2.5 GB, and from then on it works 100% offline. No account, no API key. Until you turn it on, the reader, editor and workspace work just the same.

The Keymark AI panel next to a document, with a summary whose points cite the sections they come from. The Keymark AI panel next to a document, with a summary whose points cite the sections they come from.
Fig. 2 A summary from Keymark AI. Each point cites the section it comes from.
  • Answers you can check. Every answer cites the sections of the document it comes from, like §4, and says so when the document doesn’t contain the answer.
  • Ask, explain, summarize, translate. Or make a doc actionable, from the AI panel or the ⌘K palette.
  • Edit with AI. Ask for a change and review it as a diff before anything is saved.

Edit with AI

Ask “fix the spelling” or “add an installation section”. Keymark AI proposes the change as a diff, and you apply or discard it. Your document never changes without your OK.

Proposed edit · README.mddiff
  ## Install
- Keymark keeps you’re files exactly as they are.
+ Keymark keeps your files exactly as they are.
“Fix the spelling.” Nothing changes until you press Apply.

Turn it on

  • Install Keymark. A light download. The reader, editor and workspace work right away.
  • Turn on Keymark AI. One click inside the app and a one-time download of ~2.5 GB.
  • Ask, offline. From then on it runs 100% on your computer, without internet. Your documents never leave it.

Want better answers? Keymark AI Plus is more accurate, with a bigger download, and Keymark AI Pro gives the best quality on computers with 32 GB of RAM. Both are optional and run on your computer too.

Tip

Ask about an English document in Spanish, or the other way around. The AI can also translate the whole document.

§3Since you last read

See what changed since you last read.

Docs change, especially the ones AI agents keep rewriting. Keymark remembers what you read and marks new and changed sections the next time you open the file. No git needed.

Keymark with a banner saying two sections changed since the last read, an amber bar next to a modified list and a green bar next to a new section. Keymark with a banner saying two sections changed since the last read, an amber bar next to a modified list and a green bar next to a new section.
Fig. 3 Since you last read: a modified list and a new section, marked in the margin.
  • Works on any file, inside a repo or not
  • Show the changes, summarize them with AI or mark as read
  • The summary is generated on your computer

§4Run sheet

Turn a doc into a checklist.

The Run sheet pulls the tasks and shell commands out of a setup guide or an agent’s plan and turns them into a checklist with progress.

Run sheet setup.md 1 of 3 done
  • pnpm install
  • pnpm dev

Keymark never runs commands. Copy them into your terminal and check them off.

The Run sheet panel listing a document’s tasks as a checklist with a progress bar. The Run sheet panel listing a document’s tasks as a checklist with a progress bar.
Fig. 4 The Run sheet, next to the document it came from.
  • Progress you can see at a glance
  • Copy any command into your terminal
  • Keymark never runs commands for you

§5Workspace

Open a folder. Find anything.

Open a whole project and get a sidebar with related files, your AI agent docs grouped together (AGENTS.md, CLAUDE.md, plans), backlinks and document health.

The Keymark command palette open over a workspace, listing files and commands, with the file sidebar on the left. The Keymark command palette open over a workspace, listing files and commands, with the file sidebar on the left.
Fig. 5 The ⌘K palette: files, headings, commands and questions in one place.
  • Full-text search across the folder
  • A ⌘K palette for files, headings, commands and questions
  • Broken links and missing images, flagged

§6Editor

Edit without wrecking your files.

Switch to a CodeMirror editor, or use split view with synced scrolling. Saving is byte-exact: Keymark keeps your encoding and line endings, so your diffs stay clean.

Split view: Markdown source on the left and the rendered document on the right. Split view: Markdown source on the left and the rendered document on the right.
Fig. 6 Split view: the source and the rendered document, scrolling together.
  • Read, Edit and Split modes: ⌘1 ⌘2 ⌘3
  • Nothing gets reformatted behind your back
  • Export to HTML or PDF

§7Privacy

Private by default. Verifiable by design.

Your documents stay on your computer. Keymark doesn’t ask you to sign up, and it shows you every network request it makes.

TopicIn Keymark
AccountNone. Download it and use it. There’s nothing to sign up for.
TelemetryOff by default. Usage statistics are only sent if you turn them on.
Privacy CenterSee every network request Keymark makes, in one list.
Offline modeOne switch blocks every network request.
Keymark AIOptional, on this computer. Once it’s on, it works offline.

Important

Your documents never leave your computer. The AI runs on your machine. Nothing is sent to a cloud AI, unless you choose to connect your own external AI server.

§8How it works

From download to answers in four steps.

  1. Download ~19 MB

    Install Keymark. It’s a light download, and reading and editing work right away.

    Keymark_0.3.0_aarch64.dmg or Keymark_0.3.0_x64-setup.exe

  2. Open a file or a folder .md or folder

    Double-click any Markdown file, or open a whole folder to get the sidebar, search and backlinks.

    ~/projects/handbook/README.md

  3. Turn on Keymark AI optional

    One click inside the app downloads it once (~2.5 GB). From then on it works without internet.

  4. Ask or request a change on-device

    Press ⌘K and type ?, or open the AI panel. Answers cite the sections they come from, and edits arrive as a diff you apply or discard.

    ⌘K ? how do I get started

§9Download

Get Keymark. Free during the beta.

Version 0.3.0 is the Founders Beta. Light download. Turn on Keymark AI whenever you want: one click, one time, and it works without internet.

macOS

Apple Silicon · M1 or later

Requires
macOS 14 Sonoma or later on Apple Silicon. Intel Macs are not supported.
Version
0.3.0 · Founders Beta
Size
~19 MB
AI
Optional. Turn on Keymark AI inside the app: ~2.5 GB, once.
File
Keymark_0.3.0_aarch64.dmg
SHA-256
a8b8753ed645044c837c60412749190c339858167880a86908b8ccbbe63bddc2
.dmgDownload for macOS

Windows Beta

Windows 10 and 11 · x64

Requires
Windows 10 or Windows 11, 64-bit (x64).
Version
0.3.0 · Founders Beta
Size
~20 MB
AI
Optional. Turn on Keymark AI inside the app: ~2.5 GB, once.
File
Keymark_0.3.0_x64-setup.exe
SHA-256
b397ca53b60ea621569d3db8b0b4b6d47c4868d5b00efc8abebc04274fc1ab4d

Preliminary build. The Windows version is newer than the Mac one, so expect a few rough edges. If something breaks, tell us.

.exeDownload for Windows
Installing the beta: what to expect

Founders Beta builds are not notarized by Apple or code-signed for Windows yet, so your computer may warn you the first time you open Keymark. That’s expected for this beta. Signed builds will come in a later release.

Keymark AI isn’t part of the installer. Turn it on from inside the app whenever you want: it downloads once (~2.5 GB) and then works offline.

macOS

  1. Open the .dmg and drag Keymark to Applications.
  2. Open Keymark. If macOS blocks it, go to System Settings → Privacy & Security.
  3. Scroll down, click Open Anyway and confirm.

Windows

  1. Run the installer.
  2. If SmartScreen shows “Windows protected your PC”, click More info.
  3. Click Run anyway.

§10Coming soon

Keymark on WhatsApp. Coming soon

We are building a WhatsApp integration so you can use Keymark from the chat too.

On your terms

It will be optional: you will decide which documents you share over WhatsApp, and everything else stays on your computer.

SoonTell me when it's ready

WhatsApp and its logo are registered trademarks of WhatsApp LLC.

§11FAQ

Questions, answered.

Short answers about the beta, privacy and the AI.

Is Keymark free?

Yes. The Founders Beta is free. Reading, editing, search, export and on-device AI on your own files are Keymark’s free core.

If we add optional paid services later, we’ll announce pricing before they launch, and early users will get founder pricing.

Does it run on Intel Macs?

No. Keymark needs a Mac with Apple Silicon (M1 or later) running macOS 14 Sonoma or later. Intel Macs are not supported.

Is the Windows version ready?

Yes, as a beta. It runs on Windows 10 and 11 (x64), and you can turn on Keymark AI there too. It’s a preliminary build, newer than the Mac one, so you may run into rough edges. Tell us what you find.

Does my data leave my computer?

No. There’s no account and the AI runs on your computer, so your documents stay on it. The only exceptions are the ones you turn on yourself: usage telemetry (off by default) or connecting your own external AI server.

The Privacy Center lists every network request Keymark makes, and offline mode blocks them all.

Can the AI change my files?

Only when you say so. When you ask for an edit, Keymark AI shows the change as a diff, and nothing is written until you press Apply. Discard it and your document stays exactly as it was.

Do I need to download the AI?

Only if you want it. Keymark AI is optional: you turn it on from inside the app with one click, and it downloads once (~2.5 GB). After that it works offline, and your documents never leave your computer. The reader, editor and workspace work without it.

For better answers you can add Keymark AI Plus (more accurate) or Keymark AI Pro (the best quality, for computers with 32 GB of RAM). They run on your computer too.

How big is the download?

The installer is light: ~19 MB for macOS and ~20 MB for Windows. Keymark AI is a separate, optional download of ~2.5 GB that you start from inside the app, only once.

Which files can it open?

Markdown files: .md and .markdown. .mdx files open for viewing. You can open a single file or a whole folder.

Which languages does it support?

The interface is available in English and Spanish. The AI can translate documents, and you can ask about an English document in Spanish (or the other way around).

Why does my computer warn me when I open it?

Beta builds aren’t notarized or code-signed yet. On macOS, go to System Settings → Privacy & Security and click “Open Anyway”. On Windows, click “More info” and then “Run anyway”. See Installing the beta for details.

Have another question? Write to [email protected]. We read every message.

Your Markdown, finally understood.

Join the Founders Beta: free, private, with optional AI that runs on your computer.

~19 MBDownload for macOS BetaWindows