Which data lives where?

Last updated October 2026

YouniqMail stores everything on your device. There is no YouniqMail account, no sync server, no usage statistics. Your mail server only receives what the email protocol provides for anyway.

The short answer

Goes to your mail server: read/unread, colored flags, tags, moves and deletions, snoozing, drafts and sent mail, including reactions and read receipts you send.

Stays on your device: notes, pinned mail, smart folders, saved searches, automation rules, contacts, follow-ups, snooze times, keys, signatures, templates, settings and the search index.

Does not exist: a YouniqMail account, a sync server, cloud backup, usage statistics or ad tracking.

What your mail server sees

YouniqMail stores these the way every other email program does. They are therefore visible in other programs too, if you set up the same account there.

What	In other programs	Note
Read / unread	Visible	The staple of every mail program.
Tags	Visible	Stored as keywords, as real labels on Gmail.
Colored flags	Partially	Apple Mail shows the same color. Other programs show only “flagged”, but the color stays stored.
Moves and deletions	Visible	Server-side, a mail lives in exactly one folder.
Drafts and sent mail	Visible	Land in their designated folders.
Snoozed mail	Half visible	The mail moves to a folder named “Snoozed” and can be seen there. Only YouniqMail knows when it comes back.
Forwarded, junk, read receipt sent	Visible	Noted on the mail as standard keywords.
Reactions	Visible	A reaction you add goes out to the others as a short mail and then sits in your Sent folder.

Your tags are yours to keep

Because tags live as keywords on the server, they are not lost when you uninstall YouniqMail. Set the account up again and YouniqMail rebuilds them from there. Other programs can read them too.

What exists only on your device

Everything that shapes how you work is known only to your machine. The email protocol simply has no room for these things.

• Notes on emails
• Pinned mail
• Smart folders and saved searches
• Automation rules: the rules themselves stay local, but their effects (setting a tag, moving) are visible everywhere
• Contacts: even after an import from Google or iCloud there is no ongoing sync
• Follow-ups and the time of a snooze
• PGP and S/MIME keys
• Signatures, snippets, templates
• Settings and license data
• The search index and all caches

Without a backup, this data is gone

There is no copy on any server. If your device is lost or breaks, notes, rules, contacts and follow-ups are gone. How to prevent that is covered in Backup and moving.

Where the data lives on your device

Emails, contacts, notes, rules and keys sit in a database file named mails. The settings, the license data and the database’s sealed key sit next to it in config.json.

Operating system:macOSWindowsLinux

~/Library/Application Support/YouniqMail/mails

Reach the folder in Finder via Go → Go to Folder and entering the path.

%APPDATA%\YouniqMail\mails

Reach the folder by entering %APPDATA%\YouniqMail into the Explorer address bar.

~/.config/YouniqMail/mails

Next to it sit two files ending in -wal and -shm. They belong to the database and must not be deleted or copied individually.

The same folder also holds subfolders, such as local_mail for the mail in local folders, attachment_cache for attachments you have opened, and logs for the log.

The database is encrypted

By default, the database file is encrypted (AES-256). Its key is sealed with the help of your operating system and cannot be opened on another device. A bare copy of the file is therefore useless there as long as the recovery key is missing. Some files next to the database, such as cached attachments, are not encrypted. More under Storage encryption.

What leaves the device

Beyond the connection to your mail server, YouniqMail talks to a few other places. Only connected services you set up yourself get to see the contents of your email.

Where	When	What is transmitted
License server	On activation, then at most once a day	License key, activation ID and a device name made of computer name and operating system. No mail data.
Update server	At launch, every six hours and on Check for Updates…	The query for which version is available for your operating system, with a random ID of the update module for staged rollout.
Sender check	When a mail appears in the list or you open it	DNS lookups for the sender’s domain (DKIM, BIMI). For BIMI, YouniqMail loads the logo from the address the sender specifies for it.
Recipient check	While writing	DNS lookups for the recipients’ domain, for instance whether it accepts mail.
Connection check	Continuously	A connection attempt to your mail server. Without a configured account, DNS lookups to public services (Google, Cloudflare, Quad9).
Sign-in with Google and Microsoft	For accounts using this sign-in	Sign-in and regular renewal of access.
Exchange Autodiscover	Only when setting up an Exchange account	Address and password to your domain’s Autodiscover service.
PGP keyserver	When you search for a key	The address you search for.
Newsletter unsubscribe	When you unsubscribe	The unsubscribe request to the address the sender specifies.
External images	When you load them	The request to the sender’s server, see External images.
Connected services	Only if you set them up	What you configured. Depending on the service, also the subject, sender or text of the mail, for instance with webhooks, Trello or Notion.

The license server belongs to the payment provider, not to YouniqMail. A one-time purchased license works fully offline after activation. A subscription has to check in with the license server at least every 14 days, otherwise Pro ends until the next check.

No statistics, no tracking

YouniqMail sends no usage data. There is no built-in analytics service, no crash reporting and no advertising ID. The app keeps working even if you keep it permanently disconnected from the internet. The only difference is that no new mail arrives.

What goes out while displaying emails is under your control at Settings → Privacy, for instance blocking external images and the handling of read receipts. The sender check and the update check cannot be switched off.

Frequently asked

Can I use YouniqMail alongside another program?

Yes. Both see the same emails, the same read status, the same folders and the same tags. Only the purely local things such as notes or smart folders remain YouniqMail’s own.

What happens to my data if I delete YouniqMail?

Your emails stay on the server; they were never only in YouniqMail. Tags and flags likewise. The local database with notes, rules and contacts is not removed automatically on uninstall, but you can delete the folder named above by hand.

Does the maker see my email?

No. There is no server in between that your mail passes through. The connection runs between your device and your mail provider, and to connected services you set up yourself.