Privacy policy

Who is responsible

Kistrl is operated by [legal entity name], [registered address]. For any question about your data, write to [contact email].

What we store

Your account. Your username, a display name if you set one, your time zone, your language and your appearance settings. Your password is never stored as you type it: we keep only a salted Argon2id hash. If you turn on two-factor authentication, we store its secret and your recovery codes.

Your mail. The messages you receive and send, their attachments and your drafts. The things you build around them: contacts, collections, workflows, calendar events, tasks, addresses and the rules you set for senders.

Technical data. A session cookie that keeps you signed in. The network address of sign-in and sign-up attempts, used for a short time to slow down password guessing. If you enable notifications, the push subscription your browser gives us. Server logs: [what is logged and for how long].

We do not ask for another email address, a phone number or your real name to create an account.

How we use it

We use your data to run the service for you and for nothing else:

• to receive, store, display, search and deliver your mail;
• to check incoming mail for spam with automated filters;
• to fetch images and other external content in a message, so that your browser does not contact the sender’s servers;
• to send the notifications you asked for;
• to keep accounts and the service secure.

We do not sell your data, we do not show advertising, and we do not use the content of your mail to build a profile of you.

Cookies

The Kistrl app sets one cookie, which keeps you signed in. It cannot be read by scripts and is not sent with requests from other sites. There are no advertising or analytics cookies.

This website sets no cookies, loads no third-party scripts and serves its own fonts.

On your device

If you use offline mail, Kistrl keeps a copy of recent mail and attachments in your browser’s storage on that device. You choose how much in Settings, under Offline mail.

Who else receives data

• The people you write to, and their email providers, receive the messages you send.
• Senders of mail with external content. When Kistrl fetches an image for you, the server hosting it sees a request from Kistrl, not from your device.
• Providers that help us run Kistrl: [hosting provider and location; object storage provider; outbound mail relay; any other processor]. They handle data on our instructions only.
• Authorities, only when a valid legal order requires it.

Where data is stored

Your data is stored in [country or region].

How long we keep it

We keep your account and mail for as long as your account exists.

• Mail you recycle or delete is removed permanently. Recycling rules you set in Settings, under Storage, run automatically.
• When your account is closed, we delete its data within [number] days. Backups are overwritten within [number] days.
• Sign-in throttling data expires on its own after a short time.

Your choices and rights

You can read, correct and delete most of your data yourself in the app. You may also ask us for a copy of your data, to correct it, to delete your account, or to stop a particular use of your data. Write to [contact email] and we will answer within [number] days.

[If the GDPR or another privacy law applies: legal bases for processing, the right to complain to a supervisory authority, and the name of that authority.]

Security

Passwords are hashed with Argon2id. Sessions use a random token held in a cookie that scripts cannot read. Two-factor authentication is available for every account. Each message opens in a sandboxed frame that cannot run scripts or reach outside servers.

No system is perfectly secure. If we learn of a breach that affects your data, we will tell you without undue delay.

Children

Kistrl is not directed at children under [minimum age], and we do not knowingly create accounts for them.

Changes to this policy

When we change this policy, we post the new version here with a new date. For material changes we will notify you by a message to your Kistrl address before they take effect.