BiliSub does not collect personal information, use analytics, or operate a developer-owned backend.

When Auto-Translation is enabled, BiliSub sends subtitle text and the target language selected by the user to third-party translation services:

• Google Translate (translate.googleapis.com, translate.google.com) — primary translation service
• Lingva (lingva.ml) — fallback translation service
• MyMemory (api.mymemory.translated.net) — fallback translation service

Only the subtitle text and selected target language are sent for translation. BiliSub does not intentionally send user identity, Bilibili account information, video URLs, or video metadata to these translation services.

When Auto-Translation is disabled, subtitle text is not sent to translation services.

BiliSub accesses Bilibili subtitle-related endpoints and CDN resources to detect and retrieve subtitle tracks available for the current video. BiliSub does not send the video URL to translation services.

BiliSub does not use analytics, tracking, advertising trackers, telemetry, or a developer-operated backend. Extension processing occurs locally on the user’s device except when subtitle text is sent to a translation service for translation.

BiliSub stores user preferences using the browser’s extension storage mechanism, including target language, font size, subtitle mode, Auto-Translation state, and subtitle panel position. These preferences may be synchronized by the browser’s own synchronization service. Translated subtitles are cached only in memory and are not persistently stored by BiliSub.

Google Translate, Lingva, and MyMemory are independent third-party services and may process submitted data according to their own privacy policies. BiliSub does not control their data processing or retention practices.