For solo lawyers and small firms

For solo lawyers: the client update you have written a thousand times

Where is my matter up to. What happens next. What will this cost. Can you send me the document. In a firm of one or three, the fee earner is also the secretary, and the correspondence that a larger practice hands to support staff lands on your desk between the work that is actually billable. The updates are not difficult. They are simply endless, and every one of them has to be precise.

MailTwin writes those from your notes. You type the points, it writes the finished email in your own words, and you read it and send it. It is for correspondence, not for the contract.

What that looks like on a Wednesday

Select the client's message in Apple Mail, type the points your reply needs to make, and MailTwin writes the complete email into the reply window — greeting, every point in full sentences; Mail appends your own signature.

You type	You get
draft back from the other side Thursday, warranties and termination still open, will call Friday to walk through	A status update that says what is settled, what is open and what happens next, without a hedge in every sentence
hearing listed 3 June 10am, they must attend, bring the bundle we sent, meet outside court 9:30	The logistics email with the date, the obligation, what to bring and where to be, in the order they need it
engagement letter attached, 2,500 on account before we start, hourly rate as discussed, sign and return	An engagement email that states the terms plainly and asks for the one thing you need back
can't advise on the tax point, that's for an accountant, happy to recommend one, everything else in my last email stands	A scope-limit email that says no clearly, offers a route, and does not undo the advice already given

The point is not that any of those is hard. It is that there are twenty of them a week and every one of them is unbillable.

The confidentiality question, answered properly

Client correspondence is not yours to hand to a third party, and that objection deserves an architectural answer rather than a privacy badge.

MailTwin has no server. There is no MailTwin account, and there is nowhere for your mail to be sent even if we wanted it. You choose the AI engine from nine. Three of them, Apple Intelligence on macOS 26 or later, Ollama, and a local OpenAI-compatible server (oMLX, LM Studio, llama.cpp), run on the Mac itself, so with those the message content stays on the Mac and is not transmitted. With a cloud provider, the request goes from your Mac straight to that provider under a key you supply and can revoke, together with a short sample of your own sent mail so the reply sounds like you. Voice learning reads sent mail locally and keeps its samples locally, under your own user account.

MailTwin makes no claim about privilege, confidentiality or professional compliance, and no software can make that claim for your practice on its own. Whether a cloud AI provider is an acceptable recipient of client correspondence under the rules you practise under, and whether a client's informed consent is needed first, is your judgement and your obligation. If your answer is that client material does not go to a cloud service, the on-device engines are a complete answer rather than a reduced version of the app.

Dates, figures and deadlines

A wrong limitation date in an email is not a typo. When MailTwin rewrites a draft you have already written, a validator checks the result before it reaches you and rejects it if a number, a date, an amount, a link or an email address has changed. That runs every time.

What it cannot do is judge whether a new sentence is true. It does not know when the hearing is. Type 3 June when the listing says 3 July and you will get 3 June in a well-composed sentence. Reading the draft before it goes is still the job, and nothing sends without you.

The firm's address and your own

Correspondence from the firm's address reads differently from an email under your own name, and both are in your Apple Mail. MailTwin learns voice separately for every mail account, from that account's own sent mail, so each keeps its own register and switching mailbox switches the voice. Nothing is shared between them.

The thread from the matter you inherited

A matter that has run for a year has a thread nobody can reread before a call. MailTwin summarizes the thread and pulls out the open actions, which is what you want ten minutes before the client rings. It also improves a draft you have already written, including inside Mail's own compose window, and translates, for the client or the opposing party who writes in another language. Everything it produces is a draft you read.

The honest version of the time saving

Christopher Naas, who makes MailTwin, says it saves him an hour or more on a busy email day. That is his experience and not a promise about your practice, and anyone quoting a precise figure for a lawyer's inbox is guessing. What holds is where the time sits: not in the advice, but in the twenty status updates around it, written at the end of a day that was supposed to be billable.

What it will not do

It is not a research tool, it does not draft pleadings or contracts, and it does not connect to a practice management system, a document store or a court portal. It does not know a deadline unless you type it. It will not read your inbox on its own, answer anyone without you, or send anything you have not looked at; there is no autonomous mode and no scheduled sending. It is macOS 13 or later only, Apple Mail only, with no iPhone or iPad app. It needs two macOS permissions on the first run, Automation for Mail and Accessibility, which is a few minutes in System Settings and cannot be automated away, because Apple deliberately does not let an app grant itself access to your mail. And if your replies are mostly one line, it will not help you much.

For bar associations and solo-practice networks

If you run a body whose members are the people described above and want to look at this properly before they do, write to [email protected] and licences for the office will come back, no conditions and nothing expected in return. Endorsements are not asked for and not implied. MailTwin is made by Smilodon AS, a one-person company in Norway, and the person who answers that address writes the code.

Common questions

Does client correspondence go to a third party?

Only if you choose an engine that is one. Three of the nine, Apple Intelligence on macOS 26 or later, Ollama, and a local OpenAI-compatible server, run on the Mac itself, so with those the message content stays on the Mac and is not transmitted. With a cloud provider the request goes from your Mac straight to that provider under your own key, with a short sample of your own sent mail for the voice. There is no MailTwin server and no MailTwin account in any configuration.

Does using it affect privilege or my confidentiality obligations?

MailTwin makes no claim about privilege, confidentiality or professional compliance. Whether a cloud AI provider is an acceptable recipient of client correspondence under the rules you practise under, and whether a client's consent is needed, is your judgement and your obligation. If the answer is no, the on-device engines are a complete answer, not a reduced one.

Could it change a figure, a date or a deadline?

When it rewrites a draft you have already written, a validator rejects the result if a number, date, amount, link or email address has changed. What it cannot do is judge whether a new sentence is true, so a wrong hearing date you typed comes back written out neatly. Read every draft before it goes. Nothing sends on its own.

Is this for drafting documents or for email?

Email. It writes correspondence from your notes inside Apple Mail, summarizes long threads and improves drafts you have written. It is not a research tool, it does not draft pleadings or contracts, and it does not connect to a practice management system or a document store.

What does it cost?

A one-time licence with a 30-day full trial and no card to start, and a five-licence pack for a small firm. The engine is separate: the three on-device engines cost nothing to run, and a cloud provider bills you directly for what you use, usually a few cents a day at ordinary volumes. The app shows a running total.

Try it on a month of matters

Thirty days, every feature, no card. A month of real client updates settles it faster than any description.

Download MailTwin →

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