Privacy Policy

1. Scope

This policy applies to the MultiSub browser extension and this product website. It does not apply to HBO Max, Chrome, GitHub, or other third-party services. Those services operate under their own terms and privacy policies.

2. Information we collect

MultiSub does not access account passwords, cookies, or login credentials, and the developer does not receive or maintain personal information, payment information, precise location, advertising identifiers, or a record of the user’s general browsing history. To provide dual subtitles, the extension locally processes the current HBO Max playback page URL and path, manifest and subtitle-resource URLs, selected track metadata, subtitle text, and player timing and state during the active page session. The extension does not include analytics, tracking pixels, advertising SDKs, or an account system. This website also contains no third-party analytics or tracking scripts.

3. Information stored locally

MultiSub uses Chrome’s local extension storage to remember the selected subtitle track and display preferences, including main subtitle mode, secondary placement, text size, outline, brightness, color, and vertical position. This information stays in the user’s Chrome profile and is not sent to us.

During an active HBO Max page session, MultiSub may publish a local JSON diagnostic snapshot into the HBO Max page DOM to help the user troubleshoot subtitle synchronization. It can contain current subtitle text, timing, track metadata, and HBO Max playback or subtitle-resource URLs. The snapshot is not transmitted to the developer and is discarded when the page is refreshed or closed.

4. HBO Max page access and subtitle processing

The extension runs only on https://play.hbomax.com/*. While a title is playing, it observes the DASH playback manifest supplied to the page, identifies available WebVTT subtitle tracks, and loads the segments required for the tracks the user selects. The current page URL and path, manifest data, track metadata, subtitle text, subtitle-resource URLs, and playback timing and state are processed locally in the browser for the user-facing dual-subtitle feature.

MultiSub does not transmit viewed title information, subtitle content, or playback activity to the developer. It does not fetch subtitles from an outside subtitle provider, generate translations, or unlock content that HBO Max has not made available in the current playback session.

5. Permissions

The extension requests only the access needed for its single purpose:

• Storage: saves subtitle selections and display preferences locally.
• Access to play.hbomax.com: adds the secondary subtitle menu, reads playback subtitle availability, and renders selected subtitles on the video page.

6. Network communication

MultiSub has no developer-operated backend. Network requests made by the extension are limited to the HBO Max resources referenced by the current playback manifest, such as the selected official subtitle segments. We do not receive those requests or their contents.

MultiSub does not execute remotely hosted code. All executable JavaScript is included in the extension package. HBO Max manifests and WebVTT subtitle files are processed only as data and are never evaluated as code.

7. Sharing, sale, and advertising

We do not sell, rent, share, or use user information for advertising, profiling, creditworthiness, or any purpose unrelated to displaying the selected subtitles. Because no extension data is sent to us, there is no developer-held user dataset to disclose to third parties.

Any use of information received from Chrome APIs complies with the Chrome Web Store User Data Policy, including its Limited Use requirements, and is limited to providing and improving the extension’s user-facing dual-subtitle functionality.

8. Retention and deletion

Local extension settings remain in the Chrome profile until the user changes them, clears extension storage, resets settings where available, or uninstalls MultiSub. Uninstalling the extension removes its locally stored extension data according to Chrome’s behavior.

Playback manifests, subtitle cues, player state, resource URLs, and diagnostic data are kept only in the active HBO Max page session and are discarded when that page is refreshed or closed.

9. Security

MultiSub minimizes data handling by processing subtitle information locally and avoiding a remote backend. The source code is publicly available for inspection. No software can guarantee absolute security, but the extension is designed to request narrow access and avoid unnecessary data transfer.

10. Children’s privacy

MultiSub is not directed to children under 13 and does not knowingly collect personal information from children. The extension does not create user accounts or collect age information.

11. Website hosting

This static website may be delivered through Cloudflare Pages. As part of normal website delivery and security, the hosting provider may process limited request information such as IP addresses, browser details, and timestamps under its own privacy terms. We do not add analytics scripts, use advertising cookies, or use hosting request data to profile visitors.

12. Changes to this policy

We may update this policy if the extension’s functionality or data practices change. The revised policy will show a new effective date on this page. Material changes will also be disclosed through the Chrome Web Store listing where appropriate.

13. Contact

Questions about this policy or MultiSub can be sent to andreychen9@gmail.com. Technical problems and reproducible subtitle sync reports can also be filed through GitHub Issues.