MailTwin
For trades and contractors: the quotes get written at nine at night
The work happens on site. The email happens afterwards, at the kitchen table, when the last thing you want to do is write four paragraphs to someone who wants a bathroom priced. But that is where the next job comes from, so you write it, and the reschedule, and the update about the tiles that are on back-order, and the variation for the extra socket the client asked for on Tuesday and will have forgotten by Friday.
MailTwin writes those from your notes. You type the price, the dates and the terms in a few words, and it writes the finished email in your own words. You read it and send it.
What that looks like at the end of a day
Select the customer's message in Apple Mail, type what the answer needs to say, 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 |
|---|---|
| bathroom 3,400 labour and materials, 3 days, start week of the 20th, 30% up front | A quote email with the price, what it covers, how long it takes, when you can start and the deposit, in your own plain register |
| can't do Tuesday now, Thursday first thing, water off for the morning, someone in to let us through | The reschedule that apologises once and tells them exactly what to arrange |
| tiles back-ordered two weeks, can fit everything else, come back for the floor, no extra charge | A delay update that shows a plan instead of a problem |
| extra socket and moving the rad is 380 on top, needs a yes before Friday, second invoice attached | The variation email that states the extra plainly and asks for sign-off before the work is done |
None of those is a hard email. That is the point. The hour at the table goes on the six easy ones, not on anything difficult.
It sounds like you, not like a firm with a marketing department
Customers choose a tradesperson partly on how they write. Short, direct, clear about money, no fuss. A reply that suddenly reads like a national chain's brochure loses the thing that got you the enquiry. MailTwin reads your own sent mail, on your own Mac, and copies your habits: how you open, how short you keep it, how you talk about price. It never writes a sign-off of its own; Mail appends your signature. If the business address and your personal one are both in Apple Mail, each keeps its own register, so the quote does not start sounding like a text to your brother.
The price is the email
A quote with the wrong figure in it is either a lost job or a lost margin. 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 what the job costs. Type 3,400 when you meant 3,900 and you will get 3,400 in a nicely written sentence. Read the quote before it goes. Nothing sends without you.
The client who changed their mind four times
The kitchen job has a thread with thirty messages in it and three different versions of what they want. MailTwin summarizes the thread and pulls out what has actually been agreed, which is what you want before the variation email goes. It also improves a draft you have already written, including inside Mail's own compose window, for the one you have typed yourself and are not sure reads right.
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, not a promise about your evenings, and anyone quoting a precise figure for a builder's inbox is guessing. What holds is the shape of it: the email time was never in one difficult message. It was in the six routine ones after dinner.
What it will not do
There is no phone app. MailTwin is Mac only, macOS 13 or later, and Apple Mail only, so it is for the office end of the job and not the van; if all of your email happens on a phone, this is not the tool for you. It does not connect to your invoicing software, your calendar or a job-management app, and it does not know what is booked. 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. It needs two macOS permissions on the first run, Automation for Mail and Accessibility, which is a few minutes of clicking in System Settings and cannot be skipped, because Apple does not let an app grant itself access to your mail. And if your replies are mostly one line, it will not help much. It is built for the quote, not the thumbs-up.
About the AI part, in plain words
MailTwin does not have its own AI. You point it at one of nine engines and it uses that. 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 is never transmitted anywhere. The rest need a key from that provider, and the request goes from your Mac straight to them along with a short sample of your own sent mail so the reply sounds like you; at ordinary email volumes that typically costs a few cents a day, and the app shows a running total. Your voice index stays on the Mac. There is no MailTwin account and no MailTwin server in the path.
Common questions
Is there a phone app? Most of my day is on site.
No. MailTwin is Mac only, macOS 13 or later, and Apple Mail only. It is for the office end of the job, the hour at the desk or the kitchen table when the quotes and the updates get written, not for the van. If all of your email happens on a phone, this is not the tool for you.
Could it change a price in a quote?
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. Type 3,400 when you meant 3,900 and you will get 3,400 in a well-written sentence, so read the quote before it goes. Nothing sends on its own.
Will it sound like me or like a big firm?
Like you. It reads your own sent mail on your own Mac and copies your habits: how you open, how short you keep it, how direct you are about money. It never writes a sign-off of its own; Mail appends your signature. If your business address and your personal one are both in Apple Mail, each keeps its own register.
Does it do invoicing or scheduling?
No. It does not connect to your invoicing software, your calendar or a job-management app, and it does not know what is booked. You type the price, the date and the terms in a few words and it writes the email around them. The invoice still comes from wherever it comes from now.
Is it a subscription?
No. One-time licence, 30-day full trial, no card to start. If you pick a cloud AI engine you pay that provider for what you use, typically a few cents a day at ordinary email volumes, and the app shows a running total. The three engines that run on the Mac itself cost nothing to run.
Try it on a month of quotes
Thirty days, every feature, no card. A month with a few jobs to price is the only test that matters.
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