Your subtitles stay on your device.

Local storage and processing.

Subtitle Overlay stores settings, downloaded subtitles, auto-restore data, and feature setup state in extension storage. The current Chrome implementation limits the auto-restore cache to 8 MB and identifies a video using a SHA-256 hash of its origin, path, query, and rounded duration.

Temporary session storage can hold parsed subtitles, timing adjustments, interruption state, and video identity to recover after page refreshes. These records are removed when the tab closes and are not sent to product analytics or synchronised to another device.

Optional Smart Sync processes a portion of tab audio locally in memory after you start it. Captured audio, recognised words, and subtitle text are not uploaded to analytics. Chrome may manage optional local speech packs separately. Where supported, the extension downloads and integrity-checks a voice-activity model after you choose to install it.

Pro licence keys, verification results, trial state, and setup state may also be stored locally.

Optional usage analytics.

In releases with the new consent onboarding, analytics stays disabled until you explicitly allow usage data sharing. Declining or choosing later does not restrict app functionality. You can change your choice in Settings → General. Older releases used a default-enabled analytics setting; turn it off in Settings or update to a release with the consent onboarding.

When you allow analytics, product events are sent to PostHog to understand feature usage, diagnose failures, and improve site compatibility. Events may include:

• Feature actions and operational measurements: extension version, matching engine, language-pack status, error category, elapsed time, trial usage, and download allowance.
• A one-way SHA-256 video URL hash, and a site hostname on subtitle load or failure events. Full URLs, paths, and queries are not uploaded to product analytics.
• A random persistent installation ID generated locally after consent. It is not tied to a named account, but it links events from the same installation.

PostHog receives the connection IP address and can retain it or derive approximate location. Those fields are present in the current analytics project. These records are not fully anonymous. Session replay is not used.

In the consent-onboarding release, withdrawal blocks subsequent analytics requests and clears the local analytics identifier and unsent analytics events. It does not delete records already received by PostHog or retract a request already received by a server. Email the developer to ask about deletion of existing records. We may need additional information to locate pseudonymous records; do not email a licence key.

Analytics retention is managed in the PostHog project. A specific retention period is not stated here because it has not yet been confirmed. Contact us for information or a deletion request.

Other external services.

OpenSubtitles

Search, automatic title-based suggestions on supported sites, and downloads send the query or detected title, filters, API key, or selected subtitle identifier to api.opensubtitles.com. These functional requests are separate from analytics consent. See OpenSubtitles’ privacy policy.

Optional model and speech downloads

The voice-activity model is currently fetched from fivestar1103.github.io/subtitle-overlay/models/silero_vad.onnx; optional permissions also cover kuiperbelt.site for a planned redirect. Chrome manages browser speech-pack downloads. Servers receive connection information such as an IP address. Local speech processing does not fall back silently to cloud speech recognition.

Gumroad

Pro activation and verification send the licence key and product identifier to api.gumroad.com. The extension stores verification details locally. Names or email addresses returned by Gumroad are not stored in the extension licence record or sent to PostHog. Purchase information held by Gumroad is covered by Gumroad’s privacy policy.

Feedback and support

An optional PostHog-hosted feedback form sends the answers you choose to submit. Contact details are optional. Email support receives the information you choose to include in your message. Do not submit passwords, licence keys, private video links, or sensitive recordings.

What product analytics does not receive.

• Subtitle text, recognised speech, video or audio recordings, screenshots, or page contents.
• Full page URLs, query strings, fragments, or unrelated browsing history.
• Your name, email, payment details, or licence key. Optional support and feedback can contain contact details that you provide yourself.

Permissions and controls.

Active-tab access and scripting display the overlay; storage remembers local data. On Chrome, tab capture and offscreen processing support explicit local Smart Sync runs. Network permissions support subtitle services, optional analytics, model downloads, and licence checks. Safari uses its own extension and website access settings; available features may differ.

• Disable usage data sharing in Settings → General.
• Disable auto-restore or Smart Sync in Settings → General.
• Remove downloaded subtitles and models through the available extension controls. Remove the extension through your browser’s extension settings to remove its local storage. Browser-managed speech packs use Chrome’s separate controls.
• Email support for questions or deletion requests concerning server-side records.

Children and policy changes.

The product is not directed at children under 13. We do not knowingly collect their personal information. Material changes to data practices will be reflected in this policy; the updated date appears above.

Contact.

Developer: Seonghwan Oh · 오성환.
Email: fivestar1103@uos.ac.kr.
English and Korean requests are welcome. See the support page for help.