日本語 ｜ English
This policy explains how RAINBOW TREE LLC (“we”) handles information in the iOS app “Stair Calculator: IRC Winders” (かんたん階段計算 in Japanese). It is the same as Settings → Privacy policy in the app.
The drawing numbers you enter and your plan names never leave your device. No account is needed. The app does not use the camera, photos, location, microphone or notifications.
The drawing numbers you enter (total rise, risers, tread, winder layout, grid cells), plan names and PDFs you make are stored only on this device. They are never sent anywhere, including to us. Nothing is stored in iCloud, so they do not move to a new phone.
We send how far you got (opened the input, got a verdict, opened the Pro page and so on) and short codes such as the stair shape (straight, L, U). Drawing numbers and plan names are not included. The advertising identifier (IDFA) is not collected.
When the app crashes, we send the device model, OS version, app version and where it crashed. It is used only to fix bugs.
The text and type of a contact message are sent to our support desk when you send it. To deliver replies we use an identifier assigned to each device the app is installed on. When you open Settings, the app uses this identifier to ask the desk whether a reply has arrived (no message text is sent).
There are no ads. We do not track you across other companies' apps or websites.
Pro purchases are handled by the App Store (Apple). We never receive card numbers or other payment details.
The information sent is used only to improve the app, fix bugs and reply to your messages. It is not shared with third parties except as required by law.
RAINBOW TREE LLC (Settings → Contact in the app)
September 27, 2026