A NOTE ON DATA
Your practice.
Your choices.
Butterfly Place operates this website. You can use the free games without creating an account or allowing analytics.
Analytics, by choice
If you allow analytics, Google receives usage and connection data to help us understand page visits and site performance. Google Analytics uses cookies to distinguish visits. Advertising storage, advertising user data and ad personalization remain disabled in this release. We do not load the Google measurement tag until you opt in.
Our analytics configuration removes query strings and fragments from the page URL and referrer we send. Approved campaign labels can be sent separately to measure how visitors found us. We do not send account emails, sign-in codes, profile names or journal text as analytics event fields. Google may process data on infrastructure outside your country. Read how Google uses information from partner sites.
Your analytics choice is stored in this browser for up to six months. You can change it below. Withdrawing permission removes this site's readable Google analytics cookies and reloads the page without the measurement tag. It does not erase data already received by Google.
Practice stays in your browser
Solved problems, game progress and Opening Bell journals use browser storage. This keeps practice working without an account. Clearing this site's browser data removes that local history and your privacy choice. Avoid putting sensitive information in journal reflections, especially on a shared device.
Accounts and saved practice
Account creation is being connected. Public signup and paid subscriptions are not open yet.
The prepared account flow uses Supabase for email sign-in codes, a private display name and time zone, and an optional cloud practice checkpoint. A checkpoint includes solved problems and recent journals only when you explicitly save it. The account page explains what is included before an upload. Session credentials are kept in the current browser tab for up to an hour; signing out clears that tab's stored session.
We will publish a working account-deletion path and support contact before opening public registration. Local practice does not automatically become cloud data.
Advertising and other services
Display ads are not active yet. The planned placement is limited to eligible Proving Ground pages; the firm pages and Tracker will stay free of display ads. Advertising consent will be handled separately before ad serving is enabled.
The market tape connects to TradingView only when you choose to load it. That connection shares information such as your IP address with TradingView under its privacy policy. Website hosting also processes connection and request data to deliver the pages.