A notes-first thinking app

Notes that find their own shape.

Capture anything — task, thought, list, reference. Cairn figures out what it is, what it connects to, and what to do with it later.

Download for macOSSee how it works →

Apple Silicon · macOS 12+WindowsLinux

EnglishالعربيةRTL ready

cairn — inbox

Inbox

Tuesday · 6 new
ship cairn hero previewnow
the orb is both the icon and the brand10:42
andy matuschak — evergreen notesyest
reply to katherine about the talkyest
capture > organize2d
ammon shea — reading the OED3d
put it down⌘ N

Graph

142 notes · 219 links
hover · click · pan

Weekly cleanup

3 suggestions · 5 min

Probably duplicates

review Q3 plan
Q3 review — what's left

Stale for 6 weeks

look into yfiles graph layout

Loose thread — 3 mentions

what notes apps get wrong
capture > organize

Capture

One bar. No decisions.
the orb belongs in the sidebar toonow
put it down⌘ N

Cairn figures out the kind later.

Where Cairn fits

Not another notes app.

Notion

A database. Powerful, but you have to design the schema before you can think.

Obsidian

A graph. Beautiful, but most of the time you just want to put one thing down.

Apple Notes

A stack of paper. Fast, but everything is at the same depth and forgets you.

Cairn

The quiet bar between them. Capture first, decide later — if at all.

The thinking surface

Three habits, one quiet system.

put it down…⌘ N
review Q3 plan
maybe split the onboarding
heliotrope launch notes

Capture

Just put it down.

One bar. No folders, no tags, no decisions. Type it, land it, move on — Cairn will figure out what kind of note it is later.

# launch

Clean Up

Loose ends, found.

Each week, Cairn surfaces what has drifted — duplicates, sprawling threads, stale tasks. You spend five minutes; the graph gets sharper.

Graph

Your mind, mapped.

Every note quietly connects to its neighbors. Hover one and the related notes light up. Zoom out and see your thinking from above.

On the horizon

What we’re building next.

Cairn ships slowly, on purpose. A look at what’s brewing.

  • Next

    Encrypted sync

    End-to-end encrypted mirror across your devices. Local-first, always.

  • Next

    Mobile capture

    A pocket-sized capture bar for the thought that arrives between things.

  • Soon

    Daily review

    Each morning, one quiet prompt: what's still alive, what can rest.

  • Soon

    Suggested cleanups

    Cairn proposes merges, splits, and links. You decide what sticks.

  • Exploring

    Shareable notes

    Publish a single note with one click — your vault stays private.

  • Exploring

    Plugin surface

    A small, sharp API for the few things you'd want to build on top.

One email, when it matters

Want to know when sync ships?

I’ll send one short note when encrypted sync rolls out — and nothing else. No newsletter, no promotions.

Why Cairn

Most notes apps ask you to decide first.

Pick a folder. Pick a notebook. Pick a tag, a project, a workspace, a database, a template. By the time the page is ready for your thought, the thought is gone — or worse, it’s been quietly shaped to fit the box.

Cairn flips that. You don’t decide; you just put it down. A task, a fragment, a quote you want to remember, a thread you’ll come back to. One bar, no choices. Later — when it’s easier — Cairn helps you see the shape it was always going to have, and connects it to everything else that’s adjacent.

It’s local-first because your thinking belongs to you. No account required to start. No tracking. The cloud, when it arrives, will be an encrypted mirror — opt-in, never the point.

Cairn is built by one person, slowly, on purpose. The goal isn’t to be the most powerful tool. It’s to be the quietest one — the one that gets out of the way of the thought.

“For people whose minds move fasterthan their hands.”

— AJ, building Cairn

Try it — right here

Put something down.

Type a thought, a task, a quote — anything. Cairn quietly figures out what kind of note it is.

Your notes will land here.

try: “review Q3 plan”

From people using it

Finally, an app that doesn't make me decide first. I just put the thing down and it sorts itself out.

— early beta · researcher

It's the only place I trust to land a half-formed thought without explaining myself.

— early beta · writer

I built it because I needed it. I keep it open because I still do.

— AJ · maker, daily user

Common questions

You probably want to know.

Is Cairn really local-first?
Yes. Your notes are stored on your device — in your operating system's local application data directory — and nothing is sent to any server unless you opt into sync. You can use Cairn fully offline, forever, without an account.
What about privacy?
I collect as little as possible. No analytics on note content, no tracking, no ads, no selling of data — ever. When AI features are used, prompts go to the Claude API and are not used to train any model. Full details in the Privacy Policy.
When does sync ship?
It's next on the roadmap. The plan is end-to-end encrypted sync over an opt-in hosted backend, with your notes remaining the source of truth on your device. No fixed date — I ship slowly, on purpose.
Why no folders?
Folders force a decision at the moment of capture, which is exactly when decision-making is the most expensive. Cairn uses a single, flat capture bar and figures out connections later — through the graph, weekly cleanups, and quiet structural hints.
Does Cairn use AI?
Optionally. AI features like suggested links and cleanup proposals are powered by the Claude API. They're scoped, on-demand, and never run on your notes in the background. You stay in control.
What does it cost?
Free during beta. If paid features arrive later, I'll give notice and updated terms before charging anything. The local-first core will always be usable.
Who builds Cairn?
One person — AJ. There is no company, no investors, no growth team. This is a small thing made carefully. You can email me at aj@trycairn.io.
What platforms?
macOS, Windows, and Linux today. A mobile capture companion is on the roadmap.
What languages? Is RTL supported?
English and Arabic (العربية), with full right-to-left layout — the capture bar, note list, graph, and cleanup view all flip cleanly when you switch to Arabic. More languages will come as people ask for them.

For the hands that keep up

Built around the keyboard.

⌘Ncapture
⌘Kjump to anything
⌘⇧Lweekly cleanup
⌘Gopen graph
⌘/shortcut hint

Ready when you are

Start putting things down.

Cairn runs on your machine. Local-first, no account required — encrypted sync across devices is coming soon.

Recommended for you

macOS

Apple Silicon · macOS 12+

Download.dmg

Windows

Windows 10 · 11 · 64-bit

Download.exe

Linux

AppImage · x86_64

Download.AppImage
~14 MBmacOS 12+ · Windows 10+ · LinuxEnglish · العربيةno accountno telemetryworks offlineauto-updates

Free during beta

A short note

Cairn is built by one person. There’s no team, no investors, no growth strategy. I’m making the thing I wished existed when I was trying to think clearly about anything.

If you download it and it doesn’t fit your brain, I’d love to hear why. aj@trycairn.io.

Download for macOS

AJ · Cairn