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 macOS See 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. #tag, due:tomorrow, every monday — parsed inline. Paste a URL and it becomes a reference with the page title fetched in the background. Opt+Space captures from anywhere, even when Cairn isn't focused.

what themes keep coming up?

grounded in 3 notes

Rest keeps showing up as a design problem, not a break.

save as thread →

Ask

A second mind that already knows your notes.

Ask a question and Cairn answers grounded in what you've actually written, citing its sources. It can propose creating, linking, tagging, or archiving notes — each one a card you approve. Save any exchange straight into a thread.

# launch

Clean Up

Loose ends, found.

Cairn surfaces what has drifted — duplicates, sprawling threads, stale tasks. Each week, From the cairn brings one older note back for a second look.

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.

the shape of rest

Sundays used to feel like a deadline. What if I just…

you've thought about this

→ reading lists for the weekend

→ why I keep moving the gym session

Threads

Long-form, with memory.

When a thought grows beyond a sentence, promote it to a thread. As you write, Cairn quietly surfaces older notes echoing the same idea — one click links them. Publish to the web with one button.

RESOLVED

THREADS

1.4k

WORDS

STREAK

Summit

A quiet weekly review.

Each week, Summit shows what you resolved, what you started, how many words you wrote, your streak — and on the AI plan, the themes you've been circling.

Obsidian

Notion

Apple Notes

Roam

Bear

Day One

woven into your vault

Import

Bring your past with you.

Obsidian, Notion, Apple Notes, Roam, Bear, Day One, Things, Reminders. Optional AI tidy and auto-connect on import — your notes arrive already woven in, not as islands.

Pricing

Pick what fits your thinking.

Cairn works fully on your device, free, forever. Add sync or AI when you're ready.

LocalFree

The full app, on this device.

Unlimited notes, threads, lists, spaces
Connections graph & smart Clean Up
All themes, orb variants & textures
Import from 9 sources (Obsidian, Notion, Apple Notes, Roam, Bear, Day One, Things, Reminders, plain Markdown)
Export your vault any time — no lock-in
BYO API key for AI (Claude or OpenAI)

Download to start

Cloud Sync$3/mo

Your notes on every device.

Everything in Local
End-to-end encrypted sync across devices
Desktop, mobile & web
Co-owned Spaces for collaboration
Publish threads to the web
Watched folders & continuous import

Upgrade in app

Cairn ships slowly, on purpose.

The latest cairn we stacked — and a glimpse of what’s next.

link the launch notes to this thread?

proposed · linkNotes

“heliotrope launch notes” ↔ “the shape of rest”

AcceptReject

2 sources citedsave as thread →

Latest · v0.6.0 · AskJuly 5, 2026

Ask

Ask becomes a first-class way to think with Cairn, and the mobile app catches up completely.

Full changelog →

One email, when it matters

Want to know when voice capture ships?

I’ll send one short note when voice capture 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.

Is sync available?

Yes. End-to-end encrypted Cloud Sync is available on the $3/mo plan — your notes mirror across every device you sign in on, and the local copy stays the source of truth. The Cairn AI plan ($9.99/mo) includes Cloud Sync.

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. The Cairn AI plan ($9.99/mo) bakes Claude in — Ask, Tidy, Format, tag suggestions, and weekly Summit themes, with no API key required. Or bring your own Anthropic / OpenAI key for free. AI never runs in the background; you trigger every call.

What does it cost?

Local is free, forever — the full app on your device. Cloud Sync is $3/mo (notes on every device, end-to-end encrypted). Cairn AI is $9.99/mo (sync + AI included). Cairn Unlimited is $29.99/mo for daily heavy use. You can use the app fully without paying — sync and AI are upgrades, not gates.

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. End-to-end encrypted sync across every device is one click away.

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

Local tier free forever · see pricing · v0.5.0

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