Curtilage

Privacy policy

MailPorter privacy policy

How MailPorter handles your information.

Last updated:

Summary

  • MailPorter is an email app. It connects to the mail servers you set up, and your mail is stored on your phone in the app's private storage.
  • The current version we distribute (November 4, 2026) does not send usage analytics. Versions downloaded before that date did send usage analytics: which app version you run, basic phone details, and the names of features you use, never the content of your email. Update to stop it (see Analytics).
  • The app's AI writing tools run on your phone, either inside MailPorter or in our BrainTrust app if you have it installed. MailPorter has no setting that sends your email to an AI server.

What the app collects

  • Your email accounts: your address, server names, user name, and password or sign-in token. The app needs these to fetch and send your mail.
  • Your mail: messages, attachments and folders that the app downloads from your mail server.
  • Your contacts, if you allow it: the app reads your phone's contacts to suggest addresses while you type and to show contact pictures. It does not copy your contact list anywhere else.
  • Your settings: display, notification and AI preferences, including any reply rules and the "About me" text you write for AI replies.
  • Encryption keys, if you use them: if you create an OpenPGP key in the app, your secret key is stored on your phone.
  • Usage analytics: none in the current version. See Analytics for older versions.

Where it goes

On your phone

  • Accounts, messages, attachments and settings are kept in the app's private storage on your phone. Other apps cannot read that storage. The app does not add its own encryption to this mail database. It relies on Android's storage protection.
  • Two items get extra protection. If you create an OpenPGP key in the app, its secret part is encrypted with a key held in Android's Keystore. An AI service key, if one is stored, is protected the same way.
  • On-device AI models (about 0.8 to 2 GB each) are stored in the app's storage.
  • The app turns off Android app backup, so Android's cloud backup does not copy its data.

Your own server

  • Your mail servers. The app connects to the incoming and outgoing mail servers you set up (IMAP, POP3, SMTP or JMAP). IMAP is the Internet Message Access Protocol, POP3 is Post Office Protocol version 3, SMTP is the Simple Mail Transfer Protocol, and JMAP is the JSON Meta Application Protocol. When the server supports it, the app tells your IMAP server its name and version.
  • Finding your server settings. When you add an account, the app tries to find the right settings for you:
    • It asks your email domain's own web server for a settings file, first over an encrypted connection and then, if that fails, over an unencrypted one. It sends only your domain name, not your full address.
    • It sends your email domain name to a public directory of mail settings run by a third party.
    • It looks up your domain's mail exchanger (MX) records in the Domain Name System (DNS), and then repeats the two steps above for the domain that handles your mail.
  • Sign-in with your email provider. For some large email providers, you can sign in through the provider's own sign-in page (OAuth, an open standard for authorization) instead of typing a password. The app opens that page, and the sign-in tokens come from that provider and are stored on your phone.
  • Pictures in emails. By default the app does not load pictures stored on other servers when you open an email. If you change this setting, opening an email lets the sender's servers see that it was opened.

Our servers

  • Analytics. None in the current version. See Analytics for older versions.
  • Update checks. If you installed MailPorter from our website, and not from an app store, the app checks our download server for a newer version. It checks when you open the app, at most once every six hours, and when you tap "Check for updates." The check downloads a small version file and sends nothing about you beyond what any web request carries, such as your phone's network address. If you agree to an update, the app downloads it from the address in that file.

A third-party service you choose

  • On-device AI model download. AI tools are on by default. On a supported phone, the app downloads a recommended on-device AI model automatically, once, the first time you are on an unmetered network such as Wi-Fi. The download comes from a public model-hosting website run by a third party. This happens even if you never use an AI tool. It does not happen if you remove the built-in model because BrainTrust handles your AI requests. The model then runs on your phone, and your email is not sent anywhere to use it.
  • No other third-party service receives your data from the app.

Permissions and why

  • Internet and network state
    • Why the app asks: To reach your mail servers, find server settings, check for updates and download AI models
    • When: Always present; no prompt
  • Contacts (read)
    • Why the app asks: To suggest recipients and show contact pictures
    • When: When you allow it, at setup or later
  • Notifications
    • Why the app asks: To tell you about new mail and sync problems
    • When: When you allow it (Android 13 and later)
  • Camera
    • Why the app asks: To take a photo to attach, or to scan a QR code that imports settings
    • When: Only when you choose one of those actions
  • Run at startup, keep awake, foreground service, exact alarms, sync settings
    • Why the app asks: To keep checking and pushing mail in the background on schedule
    • When: Always present; no prompt
  • Vibrate
    • Why the app asks: For notification vibration
    • When: Always present; no prompt
  • Install apps
    • Why the app asks: To install a MailPorter update you agreed to download
    • When: Android asks you once, when you first install an update
  • Bind to BrainTrust's suggestion service
    • Why the app asks: To ask our BrainTrust app for AI help, when it is installed
    • When: Granted by Android only when BrainTrust is signed by us

Analytics

The current version of MailPorter we distribute, published November 4, 2026, does not send usage analytics.

Versions downloaded from our website before November 4, 2026 sent usage analytics to our own analytics server, starting when the app was opened. What those versions sent:

  • That the app was opened, and the app version.
  • Your phone's Android version, phone model, language setting, time zone, and number of processor cores.
  • The name of each AI feature you use, for example proofread, suggest a subject, draft, improve, summarize, reply, smart replies, test the AI connection, and BrainTrust events such as a suggestion requested, a suggestion accepted, a persona chosen, an error, or a fallback to the on-device model.

What they did not send: the content, subjects, senders or recipients of your email, your email address, your contacts, or the text you ask the AI tools to work on. Our server receives the network address your phone connects from, as any web server does.

To stop it, install the current version from our website. It installs as a new app next to the old one: in the old app use Settings, Export settings, then Import settings in the new one, and remove the old app once you are done.

Sharing with other Curtilage apps

  • BrainTrust. If our BrainTrust app is installed, MailPorter sends AI requests to it first. Both apps stay on your phone. Android connects them directly, and only when BrainTrust carries our signature. A request contains the text you asked for help with. For reply and summary requests it also includes up to 20 recent messages from the email thread, each cut to 2,000 characters, the sender names in the thread, the other person's name and email address, and the persona and tone you picked. BrainTrust may keep the other person's name and address to remember context for that person. You can turn BrainTrust off in MailPorter's AI settings, and MailPorter will use its own on-device model instead.
  • Getting BrainTrust. If BrainTrust is not installed, the app may offer a link to download it. That link opens in your web browser.
  • MailPorter does not send your data to any other Curtilage app.

Your choices

  • Turn off AI tools: switch off AI in the app's AI settings. If you do this before the first model download, no model is downloaded.
  • Stop using BrainTrust: switch off BrainTrust in the AI settings.
  • Remote pictures: keep "show pictures" set to never, or allow pictures only from your contacts.
  • Contacts: deny or remove the contacts permission in Android settings. Address suggestions from your contacts stop working.
  • Export: you can export your settings to a file. Passwords are included only if you choose that, and then they are saved unencrypted in the file. You can also save a single message as a file (EML format). Your mail itself stays on your mail server.
  • Delete: removing an account deletes its mail from your phone. Uninstalling the app deletes everything the app stored on your phone. It does not delete mail on your mail server, and it does not delete analytics we have already received.
  • Analytics: the current version sends none. If you still have an older version, see Analytics.

Children

MailPorter is not designed for children, and it has no age check.

Changes to this policy

When we change this policy, we will post the new version on this page and update the date at the top.

Contact

Questions about this policy: https://curtilage.zone/contact