2D Code Book
Privacy Policy
catscatsnekoneko ("the developer") sets out below how user information is handled in the Android app 2D Code Book (二次元コード帳).
Scope
This policy applies only to the Android app 2D Code Book (二次元コード帳).
Because information is handled differently from app to app, each app has its own policy. For other apps, see the list of privacy policies.
Information kept only on your device
Everything you register is stored only in the app's private area on your device.
- The pattern of each 2D code you scan (its black-and-white grid)
- Names, tags, the fields you define yourself and their values, and notes
- Images you attach to an item
- Sets, favourites, and your filter settings
- The words you teach for autofill, and how the areas you mark out look
None of this is sent off your device. The developer cannot see any of it.
It is also excluded from automatic backup to Google Drive, so none of it is carried over automatically when you change phones.
About the contents of a code
The app stores the pattern of the code itself. It does not extract or store the data written in the code.
A hash of the contents is stored so that duplicates can be detected, but the original contents cannot be recovered from that hash.
Advertising
This app shows ads. Ads are served by Google AdMob.
To serve and measure ads, AdMob may collect an advertising ID (a resettable identifier), device information, and approximate location derived from an IP address. This is collected by Google; the developer does not separately obtain or hold it.
- Google Privacy Policy: policies.google.com/privacy
- How Google uses information in advertising: policies.google.com/technologies/partner-sites
The code patterns, images, and text you register are never used for advertising, because they never leave your device.
Consent
If you are in the European Economic Area, the United Kingdom, or Switzerland, the app asks for your consent on first launch using Google's User Messaging Platform (UMP). You can change your choice at any time from the app's settings.
Screens with no ads
No ads are shown at all while a code is displayed on screen or while a code is being scanned. The app does not use full-screen (interstitial) or rewarded ads.
Use of the camera
The camera is used only for:
- Reading 2D codes
- Taking photos to attach to an item
- Taking photos for autofill
Photos you take are never sent off your device.
Reading text from a photo uses a model that runs on your device. No image is sent over the internet for this.
Backup files
From the settings screen you can write out everything you have registered as a single file, encrypted with a password you choose.
- It is saved wherever you choose in your device's file picker
- Once written, the app has nothing further to do with that file. It neither sends nor reads it again
- Looking after the file is up to you
- If you forget the password, it cannot be restored — not by you, and not by the developer
Permissions
Camera
As described above. If you do not grant it, you cannot scan or take photos, but you can still display what you have already registered and restore from a backup.
Internet / network state
Required to serve ads. It is not used to send anything you have registered.
Advertising ID
Used by AdMob to serve ads.
Others
Any remaining permissions are required by the libraries the app uses for advertising and for the camera. The only permission the developer declares directly is the camera.
Sharing with third parties
What you register is never provided to third parties. As it never leaves your device, there is nothing to provide.
For what Google collects in serving ads, see "Advertising" above.
Deleting your data
You can delete registered items individually within the app. Uninstalling the app removes everything stored on your device.
Backup files you have already written out remain wherever you saved them. Please delete them yourself when you no longer need them.
Children's privacy
This app is intended for people aged 13 and over and is not directed at children. It is not configured as child-directed for advertising purposes.
Changes to this policy
Any changes to this policy will be published on this page.
Contact
- GitHub: github.com/catscatsnekoneko
Effective: 27 August 2026
QR Code is a registered trademark of DENSO WAVE INCORPORATED.