Privacy

Applies to mailniño from version 1.3.2 onward, and to the mailnino.cz website. Last updated: 1 October 2026.

In short

• mailniño is an e-mail app that runs on your own computer. It has no accounts, no server for your mail, and it doesn't send your mail anywhere.
• Your mail, the search index, calendar, address book and settings all sit in one folder on your disk. Passwords are in the system keychain.
• On its own, mailniño only talks to your mail servers and to mailnino.cz (checking for a new version). Everything else, only when you ask for it.
• No ads, no tracking or analytics tools, no crash reports. We don't sell anything.

Who's responsible

Data controller: Michal Foist, company ID (IČO) 69254303, contact appsupport@mailnino.cz.

What mailniño stores on your computer

Everything in one data folder:

• Windows: %LOCALAPPDATA%\cz.pcrada.mailnino
• Linux: ~/.local/share/cz.pcrada.mailnino

It contains:

• the mail index — message headers and bodies, attachment names, text extracted from attachments and text read from scans (OCR), labels and message status. It's used for search and quick display; your mail itself stays with your provider. Attachments aren't stored as files. So they can be found by their contents too, mailniño extracts text from PDF and Office document attachments into the index (you can turn this off in Settings → Mail); it doesn't download images, videos or archives for this.
• account settings — server addresses, names, signatures (without passwords),
• calendar, address book, sorting rules, snoozed, scheduled and draft messages,
• an overview of data-box messages, if you have a data box connected,
• certificates for digital signing, if you added one from a file,
• downloaded translation models, if you turned on translation,
• the app's log (engine.log) — a technical record for troubleshooting,
• a random installation number (see Checking for a new version).

None of this is sent anywhere.

Passwords and sign-in

• Passwords for mail, data boxes and certificates, and Microsoft account sign-ins, are stored in the system keychain — on Windows in Credential Manager, on Linux in GNOME Keyring or KWallet. Only the signed-in user of the computer can access them. If the keychain doesn't work, mailniño won't save the password and will tell you why.
• For Microsoft accounts you sign in on Microsoft's own page; mailniño never sees the password, it only receives an access token, which goes into the keychain.
• The file for transferring settings to another computer does contain passwords — that's why it's always encrypted with a password you choose (AES-256-GCM).

What leaves your computer, and where to

On its own:

• your mail servers (IMAP, SMTP) — downloading and sending mail,
• Microsoft (login.microsoftonline.com) — only for Microsoft accounts, refreshing sign-in,
• mailnino.cz — checking for a new version and downloading an update (see below).

Only when you ask for it:

• a data box (ISDS — Czech data boxes, Ministry of the Interior) — it connects only when you click, because by law, signing in delivers the messages,
• looking up a company by its ID (IČO) — only the company ID goes to ARES (Ministry of Finance) or the Slovak register (Statistical Office of the Slovak Republic),
• translation models — turning on translation downloads model files (Mozilla, Amazon S3 storage). Messages are then translated on your computer, they aren't sent anywhere,
• link preview while writing a message — mailniño downloads the page you're linking to,
• images from the internet in a message — by default they aren't loaded (tracking pixels), only for senders you allow them for,
• AI (Claude Desktop, Claude Code, GitHub Copilot…) — it runs on your computer; it can access your mail only after you consent in mailniño, and only to the extent you allow. Data the AI requests is then handled by its provider under its own policies.

Checking for a new version

Depending on your settings (weekly by default; in Settings → About you can switch it to “Manually”, and then it never asks at all), mailniño asks mailnino.cz for the latest version. It sends its own version number and a random installation number — this is created at install time, carries nothing about you, and is used only so we know how many installations are in use. Like any request to a website, it also carries the IP address and system type.

The mailnino.cz website and server

• Server logs (IP address, time, page address, browser type) are kept for 30 days, then deleted. Only the server administrator has access to them. They also include the installation number from the version check.
• Statistics (how many times something was downloaded, how many installations check in) contain no IP addresses — only the country is derived from the IP address during processing, and the IP itself is not stored in them; the installation number is stored in them only as a one-way hash. They're kept indefinitely.
• The website's visitor report (which pages are read) doesn't contain the installation number.
• Protection against attacks (CrowdSec): attack records are kept for 7 days; only the attacker's IP address, the type of attack and the time go to the shared CrowdSec network.
• The server is run by netcup GmbH (Germany, Nuremberg data centre) as a processor.
• The website has no forms, accounts, ads or third-party tracking tools.

Third parties

Besides your mail provider and netcup (the website), only the ones above, and only to the extent described: Microsoft (Microsoft account sign-in), ISDS, ARES and the Slovak register, Mozilla and Amazon S3 (translation models), websites you link to (link preview), senders of images you allow, and any AI you connect yourself. We don't sell or pass anything on to anyone.

Keeping and deleting data

• Removing an account in mailniño deletes its password and sign-in from the keychain on your computer, its settings, and the local copy of its mail (the index, bodies, text from attachments and scans, snoozed and scheduled messages). The mail on your provider's server stays. Your calendar and address book stay — they're yours.
• Backups and exports (.eml, .mbox, PDF, settings transfer) are created only when you ask for them, and only where you save them. mailniño doesn't keep track of them afterwards and doesn't delete them.
• You delete everything by deleting the data folder (see above).

Uninstalling

• Windows (installed from the website): tick “Delete the application data (all your data is erased for good)” — this deletes the data folder, mailniño's passwords from the keychain, and the scheduled task for sending without the app running. Without ticking it (and when uninstalling via winget, which runs without any windows), everything stays, so mailniño can be reinstalled later without losing anything.
• Windows (MSI) and Linux (.deb, AppImage): uninstalling doesn't delete data. Delete the data folder yourself, and remove your accounts in the app first (that also removes the passwords from the keychain).
• If you connected an AI, a record of mailniño stays in its settings — remove it there.

Your rights

You're fully in control of the data on your computer. For the data on the mailnino.cz server (logs, statistics), you have the right under GDPR to access, correction, erasure, restriction of processing and objection; write to appsupport@mailnino.cz. You can file a complaint with the Office for Personal Data Protection (uoou.gov.cz).

We'll announce any change to this policy on the What's new page. The current version is always here.