Cookies and storage

What is currently needed

When you sign in, Supabase authentication uses cookies needed to maintain your private workspace session. A separate session-storage entry remembers an app-update notice you postpone. The service worker caches only fixed public offline assets; private research pages and API responses are not cached.

Optional site statistics

You may allow Vercel Web Analytics to count visits to selected public pages. When enabled, this service loads only after you choose Allow public site statistics. It measures public page views and limited request-derived information such as browser, device and approximate region. Vercel uses a short-lived request-derived visitor hash rather than analytics cookies. It is not a health profile or proof of a visitor’s identity.

Private research, administrator, authentication, participant, shared-record and unknown pages are excluded. Query strings and fragments are removed from tracked URLs. Unsafe referrers are refused. Form contents, research records and custom events are not sent by this integration. Advertising tracking remains off. See Vercel’s analytics privacy description.

Your controls

Choose Accept essential cookies to acknowledge essential storage, or Close to dismiss the notice without recording acceptance. Both actions leave site statistics off and withdraw any previous statistics choice in this browser. When statistics are enabled, Allow public site statistics is a separate optional choice. Cookie settings in the footer reopens these controls. Do Not Track and Global Privacy Control keep statistics off. This browser choice is separate from participant consent and never authorizes health-data collection, matching, or identity sharing.

Essential sign-in storage cannot be switched off without losing private workspace access. Sign out to end a session, or use browser controls to remove site cookies and storage. If the browser refuses to save a changed preference, statistics stop for the current page; clear the saved site preference before a later visit if withdrawal could not be persisted.

How the choice is remembered

The first-party canxcer-storage-choice entry uses local storage and a same-named cookie for fallback. It contains only the storage-policy identifier, accepted-essential or dismissed choice, and an expiry time. It expires after one year. The cookie uses SameSite=Lax, a site-wide path, and Secure on HTTPS. It contains no identity, health profile, authentication token, or advertising identifier.

Ordinary page refreshes and PWA updates do not reset the choice. Changed storage purposes or an expired choice may show the notice again. A separate browser or device has its own choice. Clearing site data, private browsing, browser eviction, or blocking both storage mechanisms may make the notice return; the site explains when it cannot save your choice.

The statistics preference

A separate canxcer-analytics-choice local-storage entry contains only its policy identifier, an allow or decline choice, and a one-year expiry. Essential-storage acknowledgements never grant statistics permission. No permission is assumed when this entry is absent, expired, invalid or unreadable. Withdrawal is checked before each event, including navigation from a public page into a private workspace.

Before publication

Verify the exact cookie names, providers, purposes, duration, and production-host behavior. This notice should be updated whenever a new provider or script is introduced.