Pricing
Start free. These are the prices.
Registration is open and every account starts on the free plan. These are the published prices — put here so you can decide whether it is worth your time before you sign up, not after.
Free
Bring your own key. Nothing to cancel, ever.
$0
You supply an Anthropic API key. Both halves run on it — reading your history back, and turning what you capture into events. Cairn spends none of its own model budget, and none of its own compute, on free accounts.
- 500 events, hard stop
- 1 project
- MCP access, timeline, receipts, Time Machine, diff
- Full export in the open interchange format
- No historical import — capture forward from signup
- Your key is required before captures become events
- No email ingest
- Docs and community only; no support commitment
The free tier is metered on events stored, not messages. Both limits above are live in the product today.
Subscriptions
Annual is two months free, exactly.
Personal
$19.99 / mo
or $199.90 / year
One person, one practice's worth of history.
- Included processing
- 750 messages / mo
- Projects
- 3
- Email ingest
- Yes
- Project exclusion
- —
- Support
- Best-effort email
Pro
$39 / mo
or $390 / year
More room, same one-person shape.
- Included processing
- 2,000 messages / mo
- Projects
- Unlimited
- Email ingest
- Yes
- Project exclusion
- —
- Support
Practice
$79 / mo
or $790 / year
Multi-site work, and the confidentiality controls that need it.
- Included processing
- 5,000 messages / mo
- Projects
- Unlimited
- Email ingest
- Yes
- Project exclusion
- Yes
- Support
Firm
$250 / mo
or $2,500 / year
Several people, several years, and a record that has to hold up.
- Included processing
- 20,000 messages / mo
- Projects
- Unlimited
- Email ingest
- Yes
- Project exclusion
- Yes
- Support
- Priority + scheduled call
Founding member
$690 a year, Practice tier, locked for life.
The first 25 customers. Locked means locked: the price is honoured after any repricing, for as long as the account exists.
Registration is open.
Create an account and you start on the free plan. On free, Cairn runs on your own API key — add it in settings and your notes become events.
Questions about any of this: support@cairn-ai.com