Privacy Policy

JunJun AI Subtitles (Android app and web version at junjun.app) | Last updated: October 19, 2026

JunJun AI Subtitles (the "Service") is provided by an independent developer. It turns the audio of your videos into subtitles. This policy explains what data the Service processes, why, and the choices you have.

1. Data we process

Videos and audio

• We only process a video after you choose it and tap to start recognition.
• Video images are never uploaded. The app or your browser extracts the audio on your device first, and only the audio is uploaded.
• The audio is sent encrypted to our server and passed to a third-party AI speech recognition service, which turns it into subtitle text and timing. The result is sent back to your phone or browser.
• Our server does not store the audio or the recognized subtitles; each part is discarded as soon as it has been recognized. (The only exception: for the developer and invited internal testers, the recognized subtitle text and the edited subtitles are kept for 30 days to improve recognition quality; no audio is kept. Regular users do not have this feature.)
• When you turn on speaker identification, the audio of the whole recording is temporarily stored in encrypted form, used only to send to AI speech recognition, and deleted immediately after recognition. It is not kept.
• While extracting audio, the app temporarily stores an audio file in its private storage on your phone (other apps cannot read it), and deletes it when recognition ends.

Subtitles

• In the app, your subtitles are stored on your phone; in the web version, they are stored in your browser. They are never uploaded to our server.

Usage data

• To calculate your free allowance and prevent it from being claimed more than once, we record an anonymous code and the amount of time used in the current period.
• After you sign in with a Google account (same in the app and the web version): the anonymous code is an encrypted hash of your Google account ID, and the app and the web version share the same allowance.
• App device code: an encrypted hash of your device identifier. It cannot be turned back into your identity, name or phone number. It is used to prevent free minutes from being claimed more than once and to record usage before you sign in.
• Web browser code: the web version stores a random code in your browser and sends it to the server when recognition starts, to prevent free allowance from being claimed more than once on the same computer. This code contains no personal information; the server keeps it only briefly and deletes it automatically when it expires. Clearing your browser's site data gives you a new code.

Google sign-in (app and web version)

• The web version requires signing in with a Google account; the app asks you to sign in with Google once, the first time you start recognition. When you sign in, we receive your email address, name and profile picture URL, used to show who you are (during the web version's internal testing, also to check that you are on the access list). We never receive your Google password.
• After you sign in to the web version, a sign-in cookie is set only to remember that you are signed in. This sign-in record (including the email address, name and profile picture URL above) is kept for 30 days; in the app it is kept for 1 year. It is deleted immediately when you sign out.

Subscriptions and purchases

• When you subscribe in the app, payment is handled by Google Play. We never receive your credit card or payment details. We only keep the purchase token, plan and expiry time provided by Google, to confirm your plan and restore it when you change phones.
• When you make a purchase, we give your anonymous code to Google to store with the purchase, so that refunds can be matched. This code contains no name or email address.
• If you are refunded after subscribing, the minutes you used in that period are recorded as "to be offset" and are deducted first if you subscribe again within one year. We will never charge you separately or ask you to pay; the record is cancelled automatically after one year.

Technical logs

• To troubleshoot problems, we keep technical logs that contain no audio or subtitle content, such as processing time, result codes and error messages, for up to 7 days.
• To understand service usage and prevent abuse, we keep daily usage statistics (anonymous codes and numbers only, with no audio, text or IP addresses) for up to 90 days.

2. What we do not do

• We do not upload video images or look at your photo library: the app only reads the one video you pick in the system picker and cannot see anything else in your library.
• We do not store your audio or subtitles on our server.
• We do not use your location, contacts, camera, microphone or call logs.
• We do not show ads, do not use advertising or tracking cookies, and do not sell your data.

3. Third-party services

• AI speech recognition service: receives the audio and produces subtitle text and timing. We use a paid commercial plan; the provider does not use your audio or subtitles to train models and may only keep them briefly for security and abuse detection.
• AI text processing service: when you turn subtitles into an article or meeting notes, translate foreign languages, proofread the whole text or identify speakers, the subtitle text is sent to AI for processing and is not kept afterwards. The provider does not use this text to train models.
• Cloud service: hosts our server and website.
• Human verification service: before the web version starts recognizing a new video, an automatic human check is performed. The provider uses technical signals from your browser to tell whether you are a real person, to prevent abuse by bots; we only receive a "pass or fail" result.
• Google sign-in: used to sign in to the app and the web version.
• Google Play: handles subscription payments and refunds in the app.
• These services may process data outside Taiwan. Whichever provider we use, we only send the data that is necessary and keep the commitments in this policy.
• Sharing: when you share a subtitle file or video to platforms such as YouTube, Instagram or Facebook, it is handled by that platform's app or website, and the shared content is governed by that platform's privacy policy.

4. Permissions

• Internet: to send audio for recognition and check your remaining time. This is the only permission the app requests.
• Choosing a video: uses the Android photo picker. The app only reads the video you pick and does not need permission to read your whole library.
• Saving to your gallery: after you tap to build subtitles into the video, the finished video is saved to the "Movies/AI君君字幕" folder in your gallery.
• Exporting subtitle files: you choose where to save the file in the system save screen.

5. Data retention and deletion

• Audio: discarded immediately after recognition. The temporary audio file the app stores on your phone is deleted when recognition ends.
• Subtitles: only on your device. In the app, they are deleted when you delete the subtitles or uninstall the app; in the web version, when you delete the video on the home screen or clear your browser's site data.
• Sign-in records: 30 days for the web version and 1 year for the app, or until you sign out.
• Technical logs: 7 days. Daily statistics: 90 days.
• Web browser code: kept briefly and deleted automatically when it expires.
• Subtitle records of the developer and internal tester accounts: 30 days.
• Usage data: anonymous code and seconds used, deleted automatically 12 months after your last use.
• Deleting your account: in the app, go to "Settings → Account → Delete account and cloud data"; in the web version, use "Delete account" in the account menu at the top right. This immediately deletes your email address, name, profile picture, usage and plan records. To prevent abuse, minutes to be offset after a refund (kept for up to one year) and free minutes used this week (kept until next Monday) are recorded under a code that cannot be reversed and contains no name or email address, and are deleted automatically when they expire; they are linked again if the same Google account signs in later. Deleting your account does not stop Google Play subscription charges; please cancel separately in Google Play.
• Other deletion requests: you can also email support@junjun.app. Please write from the Google account you signed in with (or include the code shown in "Settings → Device code"). We will complete the deletion within 30 days.

6. Children

The Service is not designed for children under 13 and does not knowingly collect their data.

7. Changes to this policy

When this policy changes, we update the date at the top of this page; major changes are announced in the app and on the website.

8. Contact us

Email: support@junjun.app

If this English version differs from the Traditional Chinese version, the Traditional Chinese version prevails.

The Service is made by an independent developer.