SubFine – Privacy Policy

Last Updated: March 2026
Summary: SubFine does not collect, store, or sell any personal data. All subtitle processing is done locally in your browser. External connections are made only for the specific features described below, and only when you actively use them.
1. What is SubFine?

SubFine is a browser extension that helps users manage, display, filter, and translate subtitles on video streaming websites. It works primarily within your browser. External services are contacted only for specific opt-in features (AI translation, dubbing, Premium verification) as described below.
2. Data We Do NOT Collect

SubFine does not collect, store, or transmit:

Your name, email address, or any personal identifiers
Browsing history or visited URLs
Video content you watch
Subtitle content you upload or display
Any behavioral analytics or tracking data


1. External Connections — When and Why

SubFine contacts external services only in the following specific cases:

Google Translate API (translate.googleapis.com): When you use the "Translate Subtitles" feature, subtitle text is sent to Google's translation API. No user-identifying data is included in these requests.
Google Gemini AI API (generativelanguage.googleapis.com): When you use the AI translation feature with your own Gemini API key, subtitle text is sent to Google's Gemini service using your personal API key, which is stored locally on your device and never transmitted to SubFine servers.
Google Text-to-Speech (tts.google.com): When you use the dubbing feature with the Google Translate voice engine, subtitle text is sent to Google TTS to generate audio. No personal data is included.
ElevenLabs API (api.elevenlabs.io): When you use the ElevenLabs dubbing engine with your own API key, subtitle text is sent to ElevenLabs using your personal API key, stored locally and never sent to SubFine servers.
SubFine License Server (subfine.netlify.app): When you activate or the extension validates your Premium subscription, your anonymous Device ID (a randomly generated identifier with no personal data) and your activation code are sent to our Netlify-hosted verification function. No personal information is collected or stored on our server.
GitHub (raw.githubusercontent.com): The extension may fetch a remote configuration file (CSS selectors for subtitle detection) and license data from GitHub. No personal data is sent in these requests.
QR Code Generation (api.qrserver.com): When viewing a crypto donation address in the Support section, a QR code image is generated via an external API using only the wallet address string. No personal data is sent.


1. Permissions Explained
   
   activeTab / scripting: Required to detect and interact with video players on the page you are currently viewing.
   storage: Used to save your personal preferences (subtitle font size, filter rules, API keys, Premium status) locally in your browser. This data never leaves your device under normal operation, except for the Device ID used for Premium verification as described above.
   downloads: Used exclusively to save subtitle files (SRT/VTT/TXT format) to your computer when you request it. The extension does not download any video content.
   webRequest: Used to passively monitor completed network requests in order to automatically detect subtitle files being loaded by video players. The extension reads the URL only — it does not modify, block, or capture any content from these requests.
   Host Permissions (all URLs): SubFine works across many video websites including HTML5 players embedded inside iframes on anime streaming sites and other platforms. Because these sites vary widely and new ones are continuously supported, broad host permissions are required. The extension only activates its UI when a video player is detected on the page.
2. API Keys — Your Data Stays Yours

If you use AI features (Gemini, ElevenLabs), you must provide your own API key. These keys are stored only in your local browser storage (chrome.storage.local) and are sent directly from your browser to the respective API provider. SubFine servers never receive, see, or store your API keys.
6. Third-Party Services Summary
Service Purpose When Used
Google Translate API Subtitle translation When translation feature is used
Google Gemini AI AI-powered translation When AI translation is activated with own key
Google TTS Dubbing audio synthesis When Google dubbing engine is active
ElevenLabs API AI voice dubbing When ElevenLabs engine is selected with own key
subfine.netlify.app Premium license verification On first activation and once every 24 hours
raw.githubusercontent.com Remote configuration & license data Periodically in background
api.qrserver.com QR code generation for donations Only when viewing donation/crypto section

SubFine is not affiliated with any of these services. Your use of these features is subject to the respective privacy policies of each provider.
7. Children's Privacy

SubFine does not knowingly collect any information from children under 13 years of age.
8. Changes to This Policy

If we make changes to this privacy policy, we will update the "Last Updated" date at the top. Continued use of the extension after changes constitutes your acceptance of the updated policy.
9. Contact

If you have any questions about this privacy policy or the extension, please contact us via Telegram (@SubFineSupport) or visit our website.