For accountants

Client books, client mail, your machine.

Klar filters spam inside Apple Mail, on your own Mac. The extension that reads your inbox holds no network permission, so what a client sends you stays between you and them.

Get Klar free

The duty

Confidentiality is a principle, not a setting.

Confidentiality is one of the five fundamental principles of the ICAEW Code of Ethics: you respect the confidentiality of information acquired through professional and business relationships, and you do not disclose it without the client's authority. The Code then goes further than the headline. It asks you to take reasonable steps to ensure that the people whose assistance you rely on respect that duty too.

A practice inbox is a stream of exactly the material the principle is about: statements, valuations, a client's plans before they are public, and the one message in March that explains why the numbers moved. Putting a filter in front of it is not forbidden. It is a decision you carry, including for the provider behind it.

ICAEW Code of Ethics: the fundamental principles

How Klar answers it

Nothing to disclose, because nothing is sent.

Klar is a Mail extension. It scores each message on your Mac as it arrives and writes nothing anywhere else. There is no third party in the path, so there is no disclosure to authorise, no processor to bind, and no server holding a copy of your client's year.

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

Will it slow Mail down when we are busy?

Classification is instant, on your Mac as mail arrives. You are not waiting on a round trip to anyone's server, which is the part that usually makes filtering feel slow.

Our clients send us documents. Does any of that reach you?

No. The free App Store app has no network permission at all, so nothing it reads can be sent anywhere, attachments included. Klar reads the subject and the start of the body to classify, and that reading happens entirely on your Mac.

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 argument

Free, 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.