Privacy Policy - Site Sentry

Last updated: April 25, 2026

Site Sentry ("the Extension") is a browser extension that monitors specific elements on web pages for changes and sends notifications when changes are detected. This privacy policy explains what data is collected and how it is used.

Data Collection

Data Stored Locally

The following data is stored in your browser’s local storage (chrome.storage.local) and never leaves your device:

• Monitor configurations — URLs, CSS selectors, check intervals, content snapshots, and labels for each monitored element
• Change history — Records of detected changes per monitor (Pro feature, up to 50 per monitor)
• Webhook settings — Webhook URLs and type configurations for external notifications (Pro feature)
• Notification templates — Custom notification message templates (Pro feature)
• License state — Whether a Pro license is active (boolean flag)
• License key — Your Polar license key (if activated)
• Activation ID — Your Polar activation identifier (if activated)
• Expiration date — Subscription expiration date (if applicable)

Anonymous Analytics (Google Analytics 4)

The Extension sends anonymous usage events via the GA4 Measurement Protocol:

• extension_installed — sent once on first install
• extension_updated — sent on extension update
• weekly_active — sent once per week to measure active usage
• monitor_added — sent when a monitor is created
• monitor_removed — sent when a monitor is deleted
• change_detected — sent when a monitored element changes
• notification_clicked — sent when a notification is clicked

License Validation (Polar)

When a license key is entered, the Extension communicates with the Polar API (api.polar.sh) to:

• Validate the license key status
• Activate or deactivate the license
• Check subscription expiration (daily revalidation for subscriptions)

Only the license key and organization ID are sent. No browsing data or personal information is transmitted.

Data NOT Collected

The Extension does not collect:

• Page content or monitored text (stays in local storage only)
• Browsing history or visited URLs
• Personal information (name, email, etc.)
• Cookies or tracking identifiers from websites
• Screenshots or visual captures of web pages

Page Access

The Extension uses the tabs and scripting APIs to:

• Inject a visual element picker overlay for selecting elements to monitor
• Create background tabs to load monitored pages and read DOM content for change detection
• Open monitored URLs when a notification is clicked

Page content is processed locally for change detection (content hashing) and is never transmitted externally. Website access permissions are requested at runtime only for domains the user explicitly chooses to monitor.

Webhook Notifications (Pro)

When configured by the user, the Extension sends change notification messages to user-specified webhook URLs (Discord, Slack, or custom endpoints). These messages contain only the monitor label, hostname, and notification text — no page content or snapshots are included.

Data Retention

• Local storage data persists until you uninstall the Extension or clear browser data
• Analytics events are retained according to Google Analytics’ standard retention policy
• License data is managed by Polar according to their privacy policy

Third-Party Services

Contact

If you have questions about this privacy policy, please contact us at [email protected].

Changes to This Policy

We may update this privacy policy from time to time. Changes will be posted with an updated “Last updated” date.