For travel agents and advisors

For travel agents: one booking, eleven emails

A single trip is never a single email. There is the quote, which answers five questions and raises two more. The deposit confirmation. The balance reminder. The schedule change that arrives at six in the morning and has to be explained calmly by seven. The documents. The transfer question. The dietary request to the hotel, the room-type correction to the tour operator, and the thank-you afterwards that turns one trip into the next one. Multiply by every client with a departure this quarter.

MailTwin writes those emails from your notes. You type the points, it writes the finished message in your own words, and you read it and send it.

What that looks like on a Monday in January

Select the message in Apple Mail, type the facts the answer needs, 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
Lisbon 5 nights from the 12th, the hotel with the rooftop pool, 1,850 for two, 300 deposit holds it, balance 8 weeks out	The quote email with the dates, the hotel, the price and the payment terms, in the voice you use with clients rather than a brochure's
outbound moved to 14:20 same day, transfer rebooked, no action needed, new e-tickets attached	A schedule-change email that leads with the reassurance and puts the new time where they will find it
balance 1,550 due 3 April, transfer or card, documents come two weeks before travel	The reminder with the amount, the date, the ways to pay and what happens next, so nobody has to ask
to the hotel: two twins not a double, guest is coeliac, late checkout on the 17th if possible	A supplier request in your supplier register, short and in the order a reservations desk reads it

The point is not that any of those is hard. It is that there are eleven of them per trip, and in peak booking season they arrive faster than you can write them.

Clients on one side, suppliers on the other

The email to a couple planning their anniversary and the email to a tour operator's reservations desk are not the same voice, and you have spent years learning both by hand. MailTwin learns voice separately for every mail account, from that account's own sent mail. If client correspondence and supplier correspondence go out of separate addresses, each keeps its own register and switching mailbox switches the voice. If everything goes out of one address you get one learned voice, and you steer an individual email by what you type.

The supplier writes back in Italian

Hotels, ground handlers and small operators write in their own language, and the reply has to go back in it. MailTwin translates in both directions: the reservations desk's answer can be translated in place, and your request can be translated before it goes. The facts still come from you. Translation changes the language, not the room type.

Times, dates and the balance figure

A wrong departure time in an email is the kind of mistake a client remembers for years. 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 the flight moved. Type 14:20 when the airline said 14:02 and you will get 14:20 in a well-written sentence. Reading the draft is still your job, and nothing sends without you.

The thread with the whole trip in it

By the time a complicated itinerary departs, its thread has forty messages in it, half of them from the supplier side. MailTwin summarizes the thread and pulls out the open actions, which is what you want when a colleague's client calls while the colleague is away. It also improves a draft you have already written, including inside Mail's own compose window.

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 an agency inbox in January, and anyone quoting a precise figure is guessing. What is reliably true is where the time goes: not into the tricky multi-stop itinerary, but into the confirmations and reminders either side of it.

What it will not do

It does not connect to a booking system, a GDS, a supplier portal or a consolidator, and it does not know a fare, a room rate or whether anything is available. Every fact in a draft is one you typed. 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, so the schedule change you see on your phone at six waits until you are at the Mac. 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 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 much.

Where client details go

MailTwin has no AI of its own. You choose one of nine engines and supply the key. 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, and with those the message is never transmitted at all. With a cloud provider, the request goes from your Mac straight to that provider, along with a short sample of your own sent mail so the reply sounds like you. Your voice index stays on the Mac. Nothing goes to MailTwin, because there is no MailTwin server and no MailTwin account for it to go to.

For host agencies and consortia

If you run a host agency or a consortium and want to look at this before your members hear about it, 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 MailTwin check availability or prices?

No. It does not connect to a booking system, a GDS, a supplier portal or a consolidator, and it will not look anything up. You find the fare and the room the way you always do, type the facts in a few words, and it writes the email around them. It only knows what you typed and what was in the message you selected.

Can it write to suppliers in their language?

It translates, in both directions. A hotel's reply in Italian can be translated in place, and a request you write in English can be translated before it goes. The facts still come from you; translation changes the language, not the content.

Could it change a departure time or a balance figure?

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 the wrong flight time and you will get the wrong flight time, well written. Read every draft before it goes. Nothing sends on its own.

Do my clients' details get handed to a third party?

You choose the AI engine from nine. Apple Intelligence on macOS 26 or later, Ollama, and a local OpenAI-compatible server run on the Mac itself and transmit nothing. 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 the path.

Is it a subscription?

No. It is a one-time licence, with a 30-day full trial and no card required to start, and there is a five-licence pack for an agency. If you pick a cloud 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.

Try it on a booking season

Thirty days, every feature, no card. A fortnight of real departures tells you more than any demo.

Download MailTwin →

Other guides

Weighing it against something else? Best AI email assistant for Mac in 2026 compares six options and says who should pick each one.