For doctors and clinics
Patient mail stays on your desk.
Klar filters spam inside Apple Mail, on your own Mac. The extension that reads your inbox holds no network permission, so what a patient writes to you goes no further.
Get Klar freeThe duty
The address alone can be the diagnosis.
Patient correspondence can contain special category data. The GDPR defines data concerning health as data revealing someone's health status (art. 4(15)), art. 9(1) prohibits processing it except on specific grounds, and art. 9(3) turns one of those grounds on the person handling it being bound by professional secrecy. Not every message in a practice inbox is health data: the invoices and the rota are not. But the patient subset is, and it is the subset a filter cannot tell apart before it reads it.
Headers are not a safe middle ground either. The GDPR treats data revealing health status as health data, and a sender and recipient pair between a named person and an oncology practice reveals it whether or not anyone opened the body. That is why where the filter runs matters more here than almost anywhere else.
GDPR art. 9: special categories of personal dataHow Klar answers it
Nobody outside the practice reads it.
Klar is a Mail extension. It scores each message on your Mac as it arrives and writes nothing anywhere else. There is no provider to bind to secrecy, and no copy of a patient's message waiting on someone else's server.
The part of Klar that reads your mail is an Apple-sandboxed Mail extension shipped without the network entitlement. It is not that we promise not to send your mail anywhere. It is that macOS refuses the connection, because the permission was never requested. Classification happens on your Mac, instantly.
What that means in practice
- No network access
- The free App Store app and its Mail extension ship without the network entitlement. macOS refuses any connection they try to open. This is a permission the app does not hold, not a policy it promises to follow.
- The model ships with the app
- The classifier is a multilingual transformer inside the app bundle. Nothing is fetched when a message arrives, so it works the same on a train as it does in the office.
- No account
- There is nothing to sign up for and no licence server the free app calls. We do not know who you are, which is the only durable way to hold no data about you.
- The engine is open source
- The scoring engine is AGPLv3. Your IT people do not have to take our word for any of this. They can read it, build it, and watch what it does.
Questions your compliance officer will ask
Do you need HDS certification?
No, and the reason is worth being precise about rather than just asserting. France's HDS scheme certifies hosting health data on someone else's behalf, and French law puts the duty on you to check that a provider you entrust with patient data holds the certificate (art. R1111-8-8 CSP). The free app cannot send a message anywhere, so there is nothing of yours on our servers to certify and nothing for you to check. A cloud filter that stores or quarantines mail is a different question, because that does keep your patients' correspondence on a vendor's servers.
Our records system is already hosted. Does this still change anything?
Yes, though it is a narrower claim than it may sound. Klar only decides where spam filtering happens. If your records live in a hosted system, that is its own arrangement with its own contracts, and a spam filter does not touch it. What changes is that your inbox stops being a second, quieter copy of patient correspondence sitting on a filtering vendor's servers.
Does anything at all leave the machine?
Not from the free App Store app: it has no network permission. Klar Plus, the paid companion you install yourself, uses the network in two places, a licence check and model updates. Neither one carries your mail. Sending spam samples back to improve the filter is a separate switch, and it is off until you turn it on. The full list is on the local-first page.
Do we need a data processing agreement with you?
That is a question for your own counsel, and it depends on which part of Klar you run. The free App Store app sends us nothing, so there is nothing for us to process on your behalf. Our privacy policy sets out what we hold, which for the app is nothing at all. If you turn on spam sample contributions in Klar Plus, that changes, and you should treat it as a decision to review rather than a default.
Being precise
What we are not claiming.
We are not offering legal advice, and a spam filter does not make anyone compliant. Your obligations are yours, and your bar, your regulator or your DPO is the right place to test them. What we can tell you is exactly where the software runs and what it is permitted to do, which is the part most vendors leave you to infer.
We are also not claiming perfect filtering. No filter is, and any vendor quoting you a single accuracy number is quoting a number from their corpus, not your inbox. What we will say is that being wrong about a message on your Mac and being wrong about it on someone else's server are not the same kind of wrong.
Read the whole local-first argumentFree, on the Mac App Store
Try it on the inbox you cannot risk.
macOS 14 or later, Apple Silicon. No account, no cloud, no setup. It filters in Apple Mail and nothing is sent anywhere.
