For lawyers

Client mail that nobody else reads.

Klar filters spam inside Apple Mail, on your own machine. The extension that reads your inbox holds no network permission, so client correspondence never reaches a vendor, ours included.

Get Klar free

The duty

Cloud filtering is allowed. It is also yours to police.

Rule 6.3 of the SRA Code of Conduct requires you to keep the affairs of current and former clients confidential. Nothing in it forbids a cloud spam filter, and any vendor implying your duty makes their competitor illegal is selling, not advising. What the rule does mean is that routing client mail through someone else's servers is an outsourcing decision you own.

The SRA's own guidance asks firms that outsource to consider whether the arrangement adequately protects confidential information, and notes that clients may not have agreed to their affairs being reviewed by unregulated third parties, possibly in another jurisdiction. That is real work: diligence on the vendor, terms that bind it, a view on where the servers are, and a judgement that stays yours after you sign.

SRA guidance: confidentiality of client information

How Klar answers it

The filter runs where the file already sits.

Klar is a Mail extension. It scores each message on your Mac as it arrives, in the same place the correspondence already lives, and writes nothing anywhere else. No provider to select, no terms to negotiate, no jurisdiction to assess. Not because we did that work for you, but because it never starts.

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

What happens when Klar gets a client's message wrong?

It lands in Junk on your Mac and you move it back. The mistake stays on your machine: no copy was sent anywhere and nothing about the message was reported to us. With Klar Plus, moving it back also teaches the filter, and both the correction and the model it produces stay in a sandboxed container on your Mac.

Can we roll this out across the firm?

Not centrally, and not today. Klar is a free Mac App Store app that each person installs, with no account and no admin console, which is the same property that makes it hold nothing about your firm. If the firm runs its own mail servers and wants filtering before delivery, Klar for servers is a Postfix milter in early access, and that is a conversation rather than a download.

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.