ScanLingua Privacy Policy

Last Updated: September 6, 2026

1. Introduction

This Privacy Policy explains how Hui Quan Zhong, the individual developer and operator of ScanLingua ("we", "our", or "the app"), handles information when you use the ScanLingua iOS application.

ScanLingua is a document scanning, OCR (optical character recognition), and translation app for iPhone. Its core features include document scanning, on-device text recognition, on-device translation, bilingual document display, document library management, and export to TXT and PDF formats.

2. Summary

ScanLingua is designed as a local-first application. Scanned images, OCR text, translations, and exports are processed and stored locally on your device.

We do not require account registration.

We do not upload your documents, scanned images, OCR text, translated text, saved sentences, or exported files to any ScanLingua server.

Translation is performed on your device using Apple's system Translation framework. Translation language models are managed by iOS itself and, when you first request a language pair, may be retrieved by the operating system as part of its system language management.

We use Firebase Analytics and Firebase Crashlytics, provided by Google LLC, to understand app usage, diagnose crashes, and improve app stability. These services may collect limited usage, diagnostic, device, app version, and crash-related information.

We do not use Firebase to collect the contents of your scanned documents, OCR text, translated text, saved sentences, or exported files.

3. Information We Access and Process

3.1 Camera

ScanLingua requests camera access so you can scan physical documents. Scanning uses a custom in-app camera built on AVFoundation: you frame the document and press the shutter to capture each page manually. After capture, automatic edge detection, cropping, and perspective correction are performed locally on your device using Apple's Vision framework (document segmentation) and Core Image. Scanned pages are stored in the app's local container and are not uploaded by ScanLingua.

3.2 Photo Library

ScanLingua may request read access to your photo library only when you choose to import an image for local OCR and translation, or to replace the image of an existing page. The app does not add, save, or write photos, PDFs, or other files to your photo library.

Images imported from your photo library are processed locally on your device. They are not uploaded by ScanLingua.

3.3 Local Document Storage

ScanLingua stores your documents in the app's local container on your device. Each document may include:

• scanned or imported images

• OCR text recognition results

• translated text

• exported TXT and PDF files

• document metadata such as titles and timestamps

When you delete a document, the app deletes the local document directory that contains all associated files.

3.4 Local App Settings and Cached Data

ScanLingua stores certain settings and cached app data locally on your device, such as:

• selected source and target translation languages

• offline language model download status

• PDF export preferences (text size, page margins, image inclusion)

• language preference for the app interface

• recent language pair history

These settings are stored locally to make the app function correctly and preserve your preferences across launches.

3.5 Usage, Diagnostic, and Crash Information

ScanLingua uses Firebase Analytics and Firebase Crashlytics to collect limited usage, diagnostic, and crash-related information, such as:

• app launches and basic app lifecycle events

• feature usage and app interaction events

• selected language pair identifiers and non-sensitive configuration states

• device model, operating system version, app version, language, and country or region derived from network information

• crash reports, stack traces, error logs, app state at the time of a crash, and related diagnostic identifiers

We use this information to understand how the app is used, diagnose technical issues, improve stability, and prioritize bug fixes.

We do not use these services to collect the contents of your scanned documents, OCR text, translated text, saved sentences, or exported files. Crash logs will not include OCR text, translated text, document images, or full local file paths.

4. How We Use Information

We use accessed information only for app functionality and improvement, including:

• scanning physical documents and importing images

• performing on-device OCR text recognition

• performing on-device translation using language models installed and managed by iOS

• displaying bilingual original and translated text

• managing your local document library

• generating TXT and PDF exports

• saving and searching saved sentences

• remembering your settings and improving usability within the app session and future launches

• analyzing aggregated app usage and feature performance

• detecting, diagnosing, and fixing crashes, bugs, and stability issues

5. Local Processing

The core scanning, OCR, and translation workflows are designed to run locally on your device. In the current release:

• scanned images are processed locally for edge detection and cropping

• OCR text recognition is performed using Apple Vision framework entirely on your device

• translation is performed using Apple's system Translation framework entirely on your device, with language models managed by iOS

• TXT and PDF exports are generated locally on your device

• locally saved documents and settings remain on your device unless you delete the app or clear device data

Firebase Analytics and Firebase Crashlytics may process limited usage, diagnostic, and crash-related information on servers operated by Google for analytics and crash reporting purposes.

6. Third-Party Services and Network Requests

ScanLingua may use third-party or platform services in limited cases.

6.1 Apple Translation Framework

ScanLingua uses Apple's system Translation framework to provide on-device translation. Translation language models are owned and managed by the operating system and shared with other apps. This means:

• the first time you request a new language pair, iOS may present its own language download sheet to install the required language resources

• once installed, translation operates entirely on your device without further requests from ScanLingua

• ScanLingua does not operate any translation servers and does not upload your content for translation purposes

For more information, please refer to:

• Apple Legal / Privacy: https://www.apple.com/legal/privacy/

6.2 Firebase Analytics and Crashlytics

ScanLingua uses Firebase Analytics and Firebase Crashlytics, services provided by Google LLC.

Firebase Analytics helps us understand app usage and feature interaction trends.

Firebase Crashlytics helps us collect crash reports and diagnostic information so we can identify and fix stability issues.

Firebase may process information such as app instance identifiers, Firebase installation identifiers, device and OS information, app version, language, general region information, app interaction events, crash stack traces, and diagnostic logs.

For more information, please refer to:

• Firebase Privacy and Security: https://firebase.google.com/support/privacy

• Google Privacy Policy: https://policies.google.com/privacy

• Google Analytics for Firebase: https://firebase.google.com/docs/analytics

• Firebase Crashlytics: https://firebase.google.com/docs/crashlytics

6.3 Apple Platform Services

ScanLingua also depends on Apple system frameworks and platform services for permissions, camera access (AVFoundation), photo library access, on-device document analysis and OCR (Apple Vision), and related operating system functionality.

7. Exports and Sharing

TXT and PDF exports are generated locally on your device. If you choose to share an export through the iOS share sheet, the destination app or service you select may process that file according to its own privacy policy. ScanLingua does not control how third-party apps handle shared content.

8. Data Sharing

We do not sell your personal information.

In the current release, we do not operate a user account backend or advertising network inside the app. However:

• usage, diagnostic, and crash-related information may be processed by Google LLC through Firebase Analytics and Firebase Crashlytics

• when iOS installs translation language resources at your request, Apple may process limited technical data under its own policies

• Apple and other platform providers may process limited technical data under their own policies when you download, install, or run the app through their platforms

9. Data Retention

Because ScanLingua primarily stores documents and settings locally:

• scanned documents, OCR text, translations, and exports remain on your device until you delete them or remove the app

• app preferences remain on your device until you change them, remove the app, or clear the relevant device data

• translation language resources installed by iOS remain managed by the operating system until you remove them in iOS Settings or remove the app

• saved sentences remain on your device until you delete them or remove the app

• temporary or cached app data may be replaced or removed by the app over time as part of normal operation

Firebase Analytics and Firebase Crashlytics data is retained by Google according to Firebase and Google retention practices and is used for analytics, diagnostics, and crash reporting.

10. Children's Privacy

ScanLingua is not directed to children under 13, and we do not knowingly collect personal information from children through an account system or dedicated child-facing service.

If you believe a child has provided personal information in connection with the app, please contact us.

11. Your Choices

You may:

• deny camera or photo library permissions

• revoke permissions later in iOS Settings

• delete individual documents from the in-app document library

• delete exported files from your device

• manage or remove installed translation language resources in iOS Settings (these resources are installed and managed by iOS itself)

• remove the app to stop future local storage by the app

Please note that if you deny or revoke required permissions, some app features may no longer function properly.

Removing the app will stop future local storage and future analytics or crash reporting from the app on that device.

12. Security

We take reasonable steps to design the app so that core document processing occurs locally where possible. However, no software, device, storage system, or network transmission can be guaranteed to be completely secure.

13. Future Cloud Features

If ScanLingua adds optional cloud OCR, cloud translation, sync, or AI features in the future, those features will be clearly labeled separately from the local workflow before any document content is sent off device. We will update this Privacy Policy to reflect any new data practices associated with such features.

14. Changes to This Privacy Policy

We may update this Privacy Policy from time to time to reflect product changes, legal requirements, or operational updates. When we do, we will update the "Last Updated" date above.

15. Contact

If you have questions about this Privacy Policy, you can contact us at:

Operator / Developer: Hui Quan Zhong 

Email: hqzhon@gmail.com