Privacy Policy

Last Updated: December 30, 2025

Welcome to Caption Flow. Your privacy is critically important to us. This Privacy Policy explains how we collect, use, and protect your information when you use our mobile application.

            Privacy Commitment: We believe in "Privacy by Default." Most of our features are designed
            to work entirely offline, ensuring your sensitive audio and visual data never leaves your device unless you
            explicitly choose online options (for speech recognition and/or translation), which provide feature
            improvements (e.g., accuracy, speed) due to the limitations of on-device
            models for the app's use cases.
        

1. Information the App Collects and How We Use It

A. Audio and Speech Data (Live Captions)

The Live Captions feature requires access to your device's microphone or internal audio. Depending on your settings:

Offline Mode: Audio is processed locally on your device using on-device models that you download inside the app. No audio data is ever transmitted to our servers or third parties.
Online Mode (Google STT): If you choose Google Speech-to-Text, audio data is sent to Google for transcription. This data is subject to Google’s Privacy Policy.

B. Visual and Text Data (Dual Subtitles & OCR)

The Dual Subtitles feature uses Optical Character Recognition (OCR) to detect text on your screen.

OCR Processing: Screen capture data is processed locally using Google ML Kit. The visual data stays on your device and is not stored or transmitted.
Translation: Offline translation is performed locally. If you use Online Translation (Google Translate), the extracted text is sent to Google and is subject to their privacy policy.

C. User Account Information (Premium Plan)

While free features do not require registration, our Premium Plan requires a user account.

Authentication: We use Firebase Authentication to manage accounts. We may collect your email address or third-party authentication tokens to identify your subscription status.
Language Learning Data: If you use the vocabulary saving feature, the words and translations you save are stored in our backend to allow sync across your devices.

D. Local Files (Floating Subtitles)

The Floating Subtitles feature allows you to open SRT files from your local storage. We do not upload or track the content of these files.

2. Permissions Requested

To provide its core functionality, Caption Flow requires the following permissions:

Microphone or Internal Audio Capture: Used for the Live Captions feature to capture speech for transcription. See offline vs online transcription above. This permission is requested everytime you start the feature and revoked after you stop it.
Screen Capture: Used for Dual Subtitles to recognize text from other apps or videos. This permission is requested everytime you start the feature and revoked after you stop it.
Display Over Other Apps: Used to show caption overlays while you use other apps.
Internet: Used for Premium account verification, online translation/transcription services, and downloading offline language models.

3. Third-Party Services

We use the following third-party providers for specific functionalities:

Google Cloud (STT & Translate): Only when online options are selected by the user.
Firebase (Google): For secure user authentication and account management.
Google Play Billing: To process premium subscriptions securely.

4. Data Retention and Security

We implement industry-standard security measures to protect your account data. Audio and screen capture data are processed in real-time and are never stored on our servers. Saved vocabulary data is stored securely in our backend and can be deleted by the user at any time within the app.

5. Children's Privacy

Our services do not address anyone under the age of 13. We do not knowingly collect personally identifiable information from children under 13.

6. Changes to This Policy

We may update our Privacy Policy from time to time. You are advised to review this page periodically for any changes. Changes are effective immediately after they are posted on this page.

7. Contact Us

If you have any questions or suggestions about our Privacy Policy, do not hesitate to contact us via the support email provided in the Play Store.