MailCode
Years of mail, on your own disk.
MailCode
Years of mail, on your own disk.
MailCode for macOS and Windows · Last updated 6 October 2026
MailCode does not collect your data. The app has no analytics and no tracking. Your mail, your credentials, and your settings stay on your computer, and go out only when you send them somewhere — to the mail servers you configure, and to the two services described below that act on text you hand them: translation and the AI assistant. Apart from the Windows version's licence check and its check for updates (which asks mailcode.app whether a newer version exists and sends nothing about you or your mail), nothing is ever sent to a server the developer runs.
Nothing, automatically. MailCode has no telemetry, no crash reporting service, no advertising identifiers, and no third-party analytics SDKs of any kind. The developer has no way to see your mail, your contacts, your calendar, or how you use the app.
One feature is an exception, and it is deliberate and initiated entirely by you: Reporting a problem, which sends an email from your own mail account to the developer's support address. It is described below.
MailCode stores the following locally, inside its own application storage:
None of this is transmitted to the developer. Deleting the app's data, or removing an account from within MailCode, removes it from your computer. How it is protected while it is there — encrypted credentials, TLS on every connection, the limits on who can reach it — is set out under How your data is protected.
MailCode makes network connections only to the following, and only as needed:
The Exchange (EWS), IMAP, and SMTP servers you configure. This is ordinary mail traffic to servers you or your employer control. MailCode is not an intermediary for your mail: messages sync directly between your computer and your own mail server, and never pass through a server operated by the developer.
If you connect a Microsoft 365 account, MailCode opens Microsoft's own sign-in page in the system's own sign-in window — your browser on Windows — and receives an authentication token back. Your password is entered on Microsoft's page and is never seen by MailCode or by the developer.
If you add a Gmail account with Sign in with Google, MailCode opens Google's own sign-in page — in the system's own sign-in window on a Mac, in your browser on Windows — and receives an authentication token back. Your password is entered on Google's page and is never seen by MailCode or by the developer. What MailCode does with the access you grant is set out in full under Google user data.
MailCode can translate a message, a passage you have selected, or a previewed Word, Excel or PDF attachment, and show the result in place. When, and only when, you ask for a translation, the text being translated is sent to Google's translation service to be translated and sent back. Nothing is translated in the background, on a schedule, or without you asking, and no other part of the message is sent.
Google receives that text; it is subject to Google's privacy policy. The developer is not involved and receives nothing. If you have configured the AI assistant with your own provider key, longer texts are translated by that provider instead — the threshold is yours to set in Settings › AI.
MailCode includes an optional AI assistant for proofreading, rewriting, summarising, and translating. It is off until you turn it on. When, and only when, you invoke an AI action, the text you selected — a message body, a draft, or a passage you highlighted — is sent for processing. Nothing else is sent, and nothing is sent in the background, on a schedule, or without an explicit action from you.
The Summary view is the one place where an AI request is not a thing you click on one message at a time, so it is worth stating exactly. That view sorts the day’s mail by what it wants from you, and it does that from facts the archive already holds — who spoke last, whether you were in To or in Cc, whether an invitation is attached — which are read on your computer and sent nowhere. Only the mail those facts cannot settle is offered to a model, and only if you have configured one and switched the view’s AI button on; it is off until you do, and it stays off until you turn it on. While it is on, that request is made each time the view reads the day, rather than each time you click something. What is sent is the sender, the subject and the opening line the archive had already stored — never the body, and never an attachment — and each answer is kept against that conversation so the same one is not sent twice.
The assistant runs on an API key you supply, for OpenAI, Anthropic, Mistral, or a compatible endpoint. The text goes from your computer to that provider under your own account, subject to that provider's privacy policy. The developer is not involved, receives nothing, and runs no server that the request passes through. Alternatively, under Settings › AI › Local the assistant uses a model running on your own computer — Ollama, LM Studio, Jan or llama.cpp — and then the text never leaves your computer, translation included. An AI service on another computer is used only over an encrypted (https) connection.
Windows licences are sold by Gül Yüce, under licence from the developer, through Paddle, which acts as merchant of record. Your card or payment details go to Paddle and its payment processors, never to MailCode, the seller or the developer. The seller and the developer receive what is needed to support the order: your name, email address, country and the order itself.
Licence keys are issued and checked by the developer’s licence server at
license.mailcode.app. It keeps, for each licence, the key, the order number,
and the name and email address given at checkout; and for each PC the key is activated on,
that PC’s computer name and when it was activated and last checked.
Once a licence is entered, MailCode checks it with that server about once a day. The check sends the licence key and an identifier for this PC’s activation — nothing about your mail, contacts or accounts. Deactivating a PC removes its entry. The Mac version sends no such check: its purchase is handled entirely by Apple.
MailCode is a desktop application. Your mail, contacts, calendar and credentials stay on your own computer, and travel only between it and the servers you chose to connect to. There is no MailCode server holding a copy of any of it, so no central store of user mail exists to be breached. The protections that do the work are these: data is encrypted in transit, credentials are encrypted at rest with the operating system's own keystore, the stored mail is confined to your user account, and the application itself is signed so you can verify what you are running.
safeStorage. The encryption key is held by the operating system, is bound
to your user account, and never leaves the machine; what MailCode writes to disk is the
ciphertext. This is the mechanism protecting the token that grants access to your
mailbox.Where the operating system's keystore is genuinely unavailable — a locked keychain, or a Linux desktop with no keyring — MailCode falls back to storing the credential unencrypted rather than locking you out of your own mail. This does not arise on a normal macOS or Windows installation, which is what MailCode is distributed for.
If you believe you have found a vulnerability in MailCode, please write to [email protected] with enough detail to reproduce it. Reports go to the developer directly and are acted on.
This section applies when you connect a Google account (Gmail and Google Calendar) with Sign in with Google. It states what MailCode accesses through Google's APIs, and the limits on what happens to it.
https://mail.google.com/) — to download,
read, search, send, move, label and delete messages in your mailbox, through Gmail's
IMAP and SMTP servers, as you direct in the app.https://www.googleapis.com/auth/calendar)
— to show your calendars and events, and to create, change and respond to events when
you do so in the app.openid, email,
profile) — your email address and name, to identify and label the account
in MailCode.
MailCode is a full mail client that connects to Gmail over Google's IMAP and SMTP servers,
the same way Apple Mail or Outlook does. Google's IMAP and SMTP endpoints accept only the
https://mail.google.com/ scope for OAuth (XOAUTH2) sign-in, and MailCode's
features — reading, searching, sending, marking read or unread, moving between folders,
labelling, archiving and deleting — are the ordinary operations of a mail client acting on
your instruction. MailCode does not use this access for anything beyond running the
mailbox you asked it to run.
Google user data is used only to provide MailCode's mail and calendar features to you: to show your mail and calendar, keep them in sync, search them, and carry out what you ask — sending, replying, filing, deleting. It is not used for advertising, it is not sold, and it is not used to build profiles of you or anyone else.
On your own computer. Messages, attachments and calendar data are kept in MailCode's local archive so that reading and search work offline, and the authentication token Google issues is stored locally with the account. Mail and calendar data travel directly between your computer and Google's servers. None of it is sent to, or stored on, a server operated by the developer.
Google user data is covered by the measures set out under How your data is protected. Specifically, for data received from Google's APIs:
Google user data is never shared with anyone automatically. It leaves your computer, other than to Google itself, only through the features below, each started by you:
Apart from these, Google user data is not transferred to any third party. It would be disclosed only if the law required it.
Neither MailCode nor the developer uses Google user data to develop, improve or train generalised artificial intelligence or machine-learning models. The AI assistant only processes the text of a request you make, to give you its answer.
No one at MailCode reads your Google user data. The only exception is what you send the developer yourself, such as a problem report.
MailCode's use and transfer of information received from Google APIs to any other app will adhere to the Google API Services User Data Policy, including the Limited Use requirements.
MailCode includes a Report a Problem feature. If you use it, a message is sent from your own mail account to the developer's support address. That message contains what you typed plus recent technical error entries, which may include information such as folder names, server hostnames, or error text from your mail server.
This only ever happens when you choose to send a report. You can review the report before sending it, or save it to a file instead.
An optional diagnostic log can be enabled in Settings to help troubleshoot sync issues. It is off by default, written only to your own computer, and never transmitted anywhere unless you attach it to a problem report yourself.
The mailcode.app website uses Plausible, a cookieless analytics service that counts page visits without identifying visitors. It sets no cookies and stores nothing on your device, and it is not used by the MailCode app itself. See Plausible's data policy.
MailCode is a general-purpose productivity tool rated 4+. It does not knowingly collect information from anyone, of any age, because it does not collect information at all.
If this policy changes, the revised version will be posted at this address with an updated date. Material changes affecting how data is handled will also be noted in the app's release notes.
Questions about this policy, or about privacy in MailCode generally: [email protected]