Latte-chō (ラテ帳) Privacy Policy

Last updated: October 20, 2026 ・ 日本語

Latte-chō (ラテ帳, formerly "Laterie" and "Michishirube"; "the app") is a personal practice journal for latte art. This page explains what information the app handles and where it is stored.

1. Information the app handles, and where it is stored

• Practice records, roadmap, photos and videos: stored on your device (in the browser's IndexedDB for the web version, and in the app's own files for the iPhone and Android apps). They are not sent anywhere unless you sign in (except when you send feedback, described below).
• If you sign in with Google: so that you can use the same records on other devices, the following is stored on the app's server (Cloudflare Workers and D1, operated by the developer).
  • Practice records (date, result, notes, next step), skills and domains (the roadmap), and settings
  • Information about videos and photos (type, size, date taken, YouTube video ID)
  • Downsized photos and video thumbnails (one frame of the finished cup)
  • An identifier of your Google account (the Google "sub") and a value that identifies your signed-in devices (stored only as a hash)
  The content of your videos, your Google email address, name and password, and your YouTube authorization are not stored on the server as records. The only exception is a short hold during sign-in or YouTube linking: the result (your email address, or your YouTube authorization) is kept temporarily in the server's database until your device receives it, and is deleted the moment it is received. A result that is never received becomes unusable after 10 minutes and is deleted the next time anyone starts signing in. Data is sent over encrypted connections and can be read and written only from your signed-in devices. The developer does not look at users' data except when necessary for operations such as investigating a failure.
• If you send feedback from "Settings → Feedback" (no sign-in required): the message you write, its type (idea, bug, other), a reply address (only if you write one), device information (iPhone / Android / web, the OS version and screen type, and the browser type for the web version) and the app version are stored on the app's server (D1), and the same content is emailed to the developer (using Cloudflare Email Routing). It is used only to investigate problems and to improve the app. It is not linked to your Google account or to your practice records. If you write an email address or other personal information in the message or the reply address, that is stored as well.
• If you link YouTube and choose YouTube as the place to keep videos: the practice videos you record are uploaded to your own YouTube channel. Videos are sent directly from your device to YouTube and do not pass through the app's server. Videos are "Unlisted" at first (only people with the link can see them; they do not appear in search or lists). They become "Public" (visible to everyone and in search) only if you choose "Public" in the settings or for a specific video.
• When the app shows or plays YouTube videos: it loads YouTube's player (YouTube IFrame Player API, youtube-nocookie.com) and video thumbnails (i.ytimg.com). Information needed for communication, such as your IP address and browser type, is sent to Google. In the iPhone and Android apps, because YouTube requires the embedding page to be served over https, playback goes through a relay page on the app's site (GitHub Pages), which also receives information needed for communication, such as your IP address (received by GitHub). No records or photos other than the video ID are sent.
• Fonts: the app loads fonts from Google Fonts. Information needed for communication, such as your IP address and browser type, is sent to Google. Your records, photos and videos are not sent. Fonts are saved on your device after the first load and reused.

2. How Google user data is handled

• The only permissions the app requests from Google are basic profile information for sign-in (openid and email) and uploading videos to YouTube (https://www.googleapis.com/auth/youtube.upload). The YouTube permission is requested only when you link YouTube.
• The email address received at sign-in is used only to show on your device which account you are signed in with. It is not stored on the server as a record (see above for the temporary hold until your device receives it).
• The YouTube permission is used only to upload videos you recorded in the app to your own channel. The app does not read other information, such as the list of videos on your channel or your watch history.
• Your YouTube authorization (a refresh token) is stored only on the device where you linked YouTube. During linking it is held temporarily in the server's database until your device receives it, and then deleted. Before each upload, the device sends it to the app's server to be exchanged for an access token that expires in one hour; the server does not store it.
• The app does not provide, sell or use for advertising the information it receives from Google, and no person reads it. The app's use and transfer to any other app of information received from Google APIs adheres to the Google API Services User Data Policy, including the Limited Use requirements.

3. About YouTube API Services

• The app uses YouTube API Services. When you link YouTube and upload videos, you are agreeing to be bound by the YouTube Terms of Service, and you certify that the content you upload complies with those terms. Uploaded videos are set as "not made for kids" (you can change this on YouTube).
• For how Google handles data, see the Google Privacy Policy.
• You can revoke the app's access to your YouTube account at any time from the Google security settings page, App permissions. After you revoke it, the app can no longer access YouTube.

4. Retention, signing out, unlinking and deleting data

• Data stored on the server is kept until you delete your account. When you delete your account, it is deleted from the server immediately.
• "Settings → Account → Sign out" ends sign-in on that device (records on the device and on the server remain).
• "Settings → Account → Delete account" immediately deletes your account and all data stored on the server (records on your device and videos uploaded to YouTube remain).
• "Settings → Account → YouTube → Unlink" deletes the authorization stored on your device and revokes the permission on Google's side.
• You can also revoke the permission at any time from your Google Account's third-party access page.
• Videos uploaded to YouTube can be deleted from the YouTube app or website.
• Data on your device can be deleted with "Settings → Delete data on this device".
• Feedback you sent is deleted by the developer when it is no longer needed. If you would like it deleted, please contact the developer via the "Contact" section below.

5. Sharing with third parties

The developer does not share users' information with third parties, except where required by law. The app uses no analytics or advertising tools. The server runs on Cloudflare (Workers and D1), and data is stored in Cloudflare's facilities.

6. Contact

For questions or complaints about this policy or how data is handled, please contact the developer through the contact page.

7. Changes to this policy

When this policy changes, the "Last updated" date at the top of this page is updated. When the app needs additional permissions from Google, it asks for your permission again on Google's consent screen.

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