Privacy Policy
Effective 23 September 2026
The short version
- You can read, search and play everything on Cairn without an account, and without any cookies.
- Visits are counted with a first-party beacon that stores no cookie and no persistent identifier.
- If you sign in with Google, we keep your Google account id, name, email address and picture, plus what you save, vote on and write to us.
- Questions you ask the AI features are sent to Anthropic to be answered. We do not store the text of your questions.
- We do not sell your information, show ads, or use third-party trackers.
Who we are
Cairn (the "Service", at cairn.dack2.workers.dev and any successor domain) is run by David Ackerman, an individual ("we", "us"). For anything in this policy, email cairn-support@ackermansoftware.com.
What we collect
When you visit
Each page sends one small request that records a visit: the page path, the referring site (reduced to its domain), your browser's language, a rough screen size, your approximate location (country, region and city as reported by our hosting provider from your IP address), and your device type, browser and operating system worked out from your browser's user-agent string. To count unique visitors we store a visitor hash computed from your IP address, user agent and a secret that changes every day. The hash cannot be turned back into your IP address, and it cannot link your visits across days. We do not store your IP address with visit records. Automated clients such as crawlers are not recorded.
Our hosting provider, Cloudflare, processes the network requests your browser makes (including your IP address) to deliver the Service and protect it from abuse, as described in Cloudflare's privacy policy.
Stored in your browser only
Cairn saves some things in your browser's local storage so it works the way you left it: your theme, view preferences, where you left off in each episode, and episodes you choose to keep for offline listening. This stays on your device; we never receive it. Clearing your browser's site data removes it.
When you request an episode
If you use the "Missing an episode?" form, we store what you wrote, the email address you gave, and the IP address and user agent the request came from. We use these to consider the request, to tell you when it is done, and to limit abuse of the form.
When you sign in with Google
Signing in is optional. When you sign in, Google tells us your Google account id, email address, name and profile picture address, and we store those. We also keep:
- when your account was created and when it was last used;
- your sign-in sessions: a random token in a cookie on your device, of which we store only a one-way hash, with an expiry date and your browser's user agent;
- the shows you add to your library;
- your thumbs-up and thumbs-down votes, and any notes you write to us, along with a record of what you were looking at when you wrote them;
- if AI features are enabled on your account, a usage record for each question: which episode or show it was about, which model answered, and how many tokens it used.
We never receive your Google password, and we do not get access to your Gmail, contacts, files or anything else in your Google account.
AI features
When you use "Ask about this moment" or ask across a show's episodes, your question, the parts of the transcript it concerns, and the conversation so far are sent to Anthropic, PBC, whose Claude models write the answer. Anthropic handles that data under its commercial terms and privacy policy. We keep only the usage record described above, not the text of your question or the answer. Do not put personal or sensitive information in your questions.
Cookies
Cairn uses cookies only for signing in:
| Cookie | Purpose | Lasts |
|---|---|---|
cairn_oauth | Protects the Google sign-in step from forgery and remembers which page to return you to | 10 minutes |
cairn_session | Keeps you signed in | 30 days, or until you sign out |
Both are strictly necessary for sign-in and are never set unless you start signing in. We use no advertising, analytics or third-party cookies.
How we use information
- To run the Service: sign you in, keep your library and votes, and answer your questions.
- To improve it: your votes and notes shape which highlights and topics Cairn shows, and visit counts tell us what people read.
- To decide who gets access to AI features and to keep their cost under control.
- To answer episode requests and messages, and to prevent abuse, fraud and security problems.
- To comply with the law.
Where laws such as the GDPR require a legal basis, we rely on performing our agreement with you (running your account and the features you use), our legitimate interests (keeping the Service secure, understanding its use, and improving it), and your consent where we ask for it.
Who we share it with
We do not sell or rent personal information, and we do not share it for advertising. We share it only with:
- Service providers that run parts of Cairn for us: Cloudflare (hosting, database and audio storage), Google (sign-in; and our web fonts are served from Google Fonts, which receives your IP address when a page loads them), and Anthropic (answering AI questions).
- Authorities or others when the law requires it, or when it is needed to protect the rights, safety or property of our users, the public or us.
- A successor, if Cairn is transferred to someone else, who would remain bound by this policy for information collected under it.
How long we keep it
- Account information, library, votes and notes: until you ask us to delete your account.
- Sessions: until they expire after 30 days or you sign out.
- Episode requests: until the request is handled, and afterwards as a record, unless you ask us to delete it.
- Visit records and AI usage records: as long as they are useful for statistics and cost tracking.
Your choices and rights
- You can use all of Cairn's reading, searching and listening without an account.
- You can sign out at any time from the menu under your picture.
- You can remove Cairn's access to your Google account at myaccount.google.com/permissions.
- You can ask us for a copy of your information, to correct it, or to delete your account and everything linked to it, by emailing cairn-support@ackermansoftware.com from the address on your account. We will respond within 30 days.
Depending on where you live (for example the EU, UK or California), you may have further rights, such as to object to or restrict processing, to data portability, or to complain to your local data protection authority. We honour these requests wherever they apply, and we will not treat you differently for making one.
Children
Cairn is not directed to children, and you must be at least 13 years old to create an account (or older where local law requires it, such as 16 in some EU countries). If we learn that we hold information from a child under 13, we will delete it. If you believe a child has given us information, please contact us.
Where it is processed
We operate from the United States, and our service providers process data in the United States and in other countries where they have facilities. By using Cairn you understand that your information may be transferred to and processed in those countries.
Security
Cairn is served only over HTTPS. Session tokens are stored only as one-way hashes, and access to our databases is restricted to us. No system is perfectly secure, but we will tell you and the relevant authorities of a breach affecting your information where the law requires it.
Changes to this policy
We may update this policy as Cairn changes. We will post the new version here with a new effective date, and for significant changes we will give notice on the site or by email before they take effect.
Contact
David Ackerman, operator of Cairn: cairn-support@ackermansoftware.com.