Cairn
Cairn 2.1 · self-hosted · open source
A coach that has already read your whole day, and has one honest thing to say.
The demo runs a real Cairn on fictional data in a GitHub Codespace. Nothing touches your machine.
Cairn reads your lifting, running, food, sleep, labs and life as one picture. It opens to a calm read of today: rest, easy or train, with the reasons shown. A team of specialists works quietly behind it, makes the small calls, and gives you a one-tap Undo for each one.
It runs on your own hardware, keeps everything in a SQLite file you own, and never scores you or nags you.
Today
Today opens on an answer, not a dashboard. Rest, easy or train, in one sentence, with the evidence a tap away: last night's sleep, your HRV against your own band, the load you carried this week, the knee you mentioned on Tuesday.
A suggestion, never a gate. A missing night says nothing, never "bad".
The team
Strength, endurance, nutrition, physio and an informational health seat each watch their part of you. When the evidence is clear, a bounded change lands on its own, with its why in plain words and one tap to put it back. Anything clinical, irreversible or goal-changing still asks first.
Labs
A flagged marker doesn't sit in a PDF. It travels into your meals, your training and your watch, each with its why and a citation. Before a visit, the doctor packet builds itself, in clinical order.
Informational, never medical advice.
Fuel
Type a meal the way you'd say it, or snap the plate, and it comes back as a card you can correct. Expenditure comes from your real weight trend. A thin logging week lowers confidence; it never blames you.
Horizon
Name a half marathon and Horizon draws the road to it from the weeks you actually ran. The best week you've already run safely sets the floor; the peak aims just past it. Strength keeps progressing all the way to race week.
You
Strength, endurance, fuel, recovery, body and heart, each with one word for where it stands right now. Tap a stone to see what it leans on: a ferritin still catching up quietly holds the running back.
Words and your own baseline, never a 0–100.
No terminal? One click puts Cairn on your own Railway account, about $5 a month on the Hobby plan, nothing to keep running. A sign-in token is generated for you; switch on Railway's auto updates once and new releases arrive on their own.
One command asks where Cairn should live: Railway, or this computer (free, private, Docker or Podman, nightly updates that roll back on their own). Either way it opens Cairn already signed in. Both choices, side by side →
curl -fsSL https://cairn.fit/install | shOr run the container yourself. One container, amd64 or arm64; a Raspberry Pi is plenty:
docker run -d --name cairn -p 127.0.0.1:8787:8787 \
-v cairn-data:/data -v cairn-home:/home/app \
-v cairn-tools:/home/app/.cairn-tools \
--restart unless-stopped ghcr.io/zilet/cairn:latestThen open http://localhost:8787. It opens on a fictional example athlete so there is something to look at; add -e CAIRN_BLANK_PROFILE=1 to start on the welcome instead. Quickstart →
Garmin, Apple Health, lab PDFs and your AI are connected from inside the app. Cairn uses an AI subscription you already have, Claude, ChatGPT, Google or Grok, for the coach's voice; logging, the plan and the read of today work without one.
New in 2.1: the one-command install and the Railway button, a welcome that walks you through the first run, passkeys and per-device sign-in, starter exercise pictures with no key needed, and any AI subscription you already have.