Cookie and local storage notice

Essential storage

Better Auth session cookies keep you signed in; temporary OAuth security data helps complete Google/Apple sign-in safely. Sessions can last up to 30 days; signing out ends the session. This storage is necessary for sign-in functionality.

Settings such as level, language, progress, review queue, sound preferences and currency may use localStorage. Temporary sessionStorage preserves the return from sign-in/checkout. A service worker and Cache Storage keep public application files for offline use; private account/payment API responses are not cached there.

Optional analytics

With consent on the production site, Google Analytics 4 may set _ga / _ga_* cookies, typically for up to two years depending on browser/Google settings. The chessopening-analytics-consent-v1 choice is stored in your browser. Our application does not load the Google tag before permission; GA4 is disabled on staging.

Use the analytics preferences button on pages where analytics is enabled to change your choice. Declining stops further analytics events and attempts to remove accessible GA cookies. Our application does not start analytics when DNT or GPC is enabled.

Other services

Cloudflare may use technical cookies/data to deliver and protect the site. Storage on Google, Apple and Polar pages is governed by those providers’ policies. See our Privacy notice.

Clearing data and its effects

You can delete this site’s cookies, local storage and offline cache through browser settings. This may sign you out and remove guest progress stored only on the device. It does not delete your server account or cancel a subscription.