StringinoPrivacy Policy
Last updated: October 11, 2026
This policy explains how Masaki Naito ("we") handles information in the iOS app "Stringino" (the "App").
1. Our approach
- There are no accounts. We do not collect your name, email address or address.
- No ads. No tracking, and no third-party analytics SDKs.
2. Information that stays on your device
- Microphone audio is used to measure the pitch and rhythm of your playing. It is analyzed on the device and is never saved or uploaded.
- Practice history (the pitch and timing of the notes you played), your scores and settings are stored only on your device. Deleting the app removes them.
3. What is sent when you use scan import (Pro)
Only when you use "Import from scan", the following is sent to our server (Google Cloud, Tokyo region):
| Information | Purpose | Retention |
|---|---|---|
| The image (PDF or photo) you choose | Reading the notes | Deleted as soon as reading finishes (also when it fails). As a safety net, the storage bucket also auto-deletes after 1 day. |
| The reading result (score data) | Handing it to the app | Deleted as soon as the app confirms receipt; otherwise after 24 hours. |
| A random device ID and an authentication value | Managing your requests | As long as the device stays registered (server records may outlast deleting the app). |
| Your notification address (APNs device token) | Telling you when reading is done | As long as the device stays registered. |
| Your subscription identifier (App Store transaction ID) | Verifying the subscription and enforcing the monthly limit (20 pages) | Kept as a usage count. |
| Processing logs (job ID, status, duration, AI usage) | Operations, debugging and cost control | For a limited period (the cloud provider's default). Image and score contents are not logged. |
To read the notes we use the API of Anthropic (Claude). The image is sent from our server to Anthropic for this purpose; Anthropic's privacy policy and API terms apply to its handling.
Please use copyrighted sheet music only within the scope of private use.
4. Purchases
Subscriptions are purchased and paid for through Apple. We never receive your payment details. We receive only Apple-signed transaction data (transaction ID, product, expiry) to verify that your subscription is active.
5. Sharing
We do not share information with third parties except as required by law and as described above: Google (server hosting) and Anthropic (AI reading).
6. Children
The App is designed so that children can practice with it. We do not knowingly collect personally identifiable information from children. Scan import requires a subscription, which is purchased by a parent or other adult.
7. Deletion and contact
Delete your practice history in Settings ("Delete all history"). To request deletion of server-side information (such as device registration) or to ask questions, contact [email protected].
8. Changes
If we change this policy we will post the update on this page.