Privacy Policy

KATSU · Last updated 7 September 2026

KATSU has no servers. The words you write, the routines you set, and the days you checked off never leave your phone, because there is nowhere for them to go.

What KATSU stores

Everything the app keeps is written to your device's own storage and stays there:

• The routines you add — a time and a short title.
• The messages you write to yourself.
• Which items you checked off, by day.
• Whether you have finished onboarding, and whether the graduation screen has been shown.

None of this is uploaded, backed up to us, analysed, or shared. We cannot read it. If you delete the app, it is deleted with it.

What KATSU does not collect

• No account, email address, or name. There is no sign-up.
• No analytics, tracking, advertising identifiers, or third-party SDKs for measurement.
• No location, contacts, photos, or health data.
• No logging of what you write — not on the device, and not anywhere else.

The safety check

Before a message is saved, KATSU checks it against a list held inside the app to catch expressions of self-harm or suicidal intent directed at yourself. This runs entirely on your device. The text is not sent anywhere to be checked, and the outcome is never recorded — not stored, not logged, not counted. If the check stops a message, the app tells you, offers findahelpline.com, and nothing about it is kept.

Subscriptions

The optional subscription is handled by RevenueCat, which manages purchases on our behalf. It is the only part of KATSU that talks to the network. To tell whether your subscription is active, RevenueCat receives an anonymous identifier it generates for your install, along with the purchase details Apple provides. It never receives anything you wrote.

Payment itself is handled by Apple under Apple's privacy policy. We never see your payment details.

Notifications

Notifications are scheduled locally by your phone, at the times you set. They are not push notifications — no server sends them, and the text inside them never leaves the device. You can turn them off at any time in iOS Settings, and the rest of the app keeps working.

Children

KATSU is not directed at children under 13, and collects nothing from anyone.

Changes

If this policy changes, the date at the top changes with it. Since the app collects nothing, we do not expect meaningful changes unless the app itself gains a feature that needs them — in which case it will be said here, plainly.

Contact

Questions about this policy can go to dev.kishikawa@gmail.com.