Privacy Policy

Last updated: 2 July 2026

Sentinel ("we", "us") is a website change monitoring service. This policy explains what we collect, why, and what we do with it. The short version: we collect the minimum needed to run the service, we don't sell your data, and payments are handled by a payment provider that never shares your full card details with us.

What we collect

Account data — your email address and a hashed password when you sign up.
Monitoring configuration — the URLs you ask us to watch, labels, check frequency, CSS selectors, and notification settings (including webhook URLs you provide).
Page snapshots — copies of the publicly accessible pages you monitor, stored so we can detect changes. These are pages you chose; they are not data about you.
Change events — diffs and AI-generated one-sentence summaries of detected changes.
Usage data — basic logs (sign-ins, API requests, check runs) for security, debugging, and plan limits.
Support messages — if you contact us or use the site chat, we keep the conversation to answer you and improve the service.

What we don't collect

We don't store your card details. Payments and billing are processed by Lemon Squeezy, our merchant of record, under their privacy policy. We receive only your subscription status and billing email. We don't run third-party advertising trackers.

How we use your data

To run checks, detect changes, and send you the alerts and digests you configured.
To generate AI summaries of detected changes. Page content (not your personal data) is sent to Anthropic's Claude API for summarization.
To email you service messages: digests, trial reminders, security notices. Marketing email only with your consent, and every message has an unsubscribe link.
To enforce plan limits, prevent abuse, and keep the service secure.

Where your data lives

Sentinel runs on Cloudflare's global network (Workers, D1, KV, R2). Email delivery runs through our own mail infrastructure in the EU. Because monitoring is a global service, data may be processed in multiple regions.

Sharing

We share data only with the processors needed to run the service: Cloudflare (hosting and storage), Anthropic (AI summaries of monitored page content), Lemon Squeezy (billing), and our email delivery provider. We don't sell or rent your data to anyone. We may disclose data if required by law.

Retention and deletion

Snapshots and change events are kept while the associated monitor is active, and pruned when you delete a monitor. If you delete your account, we remove your account data, monitors, snapshots, and change events within 30 days, except records we must keep for legal or accounting reasons. To delete your account, email us or use the account page.

Your rights

Depending on where you live (including under GDPR and South Africa's POPIA), you may have the right to access, correct, export, or delete your personal data, and to object to certain processing. Email us and we'll act on the request within 30 days.

Cookies

We use a session cookie to keep you signed in and a preference key in your browser's local storage for the theme. No cross-site tracking cookies.

Changes to this policy

If we make material changes, we'll email account holders and update the date at the top of this page.

Contact

Questions or requests: privacy@usesentinel.io. Sentinel is operated from South Africa.