Your cities. Your family’s controls.

Cornerstone is a private city-building game. Its budgets, taxes, jobs and growth provide the math practice. A parent gives permission for the game nicknames that parent creates and manages.

We store the parent account and email, invented game nicknames, protected sign-in credentials and sessions, current and previous city collections, named cities, tutorial progress and display settings. Use an invented nickname and city name, not personal information. There are no quiz-answer or earned-building-time records in Cornerstone.

These records provide sign-in, saved play across devices, recovery, parent controls and service security. Vercel hosts the service, Supabase provides account/database services, and our transactional-email providers deliver parent notices. Cornerstone has no public profiles, public cities, player chat, advertising or AI features. We do not sell children’s information or use it for targeted advertising.

Parents can review and download city records, delete Cornerstone cloud cities without deleting a shared nickname, or withdraw permission from the Cornerstone parent page. Withdrawal stops child access immediately. Scheduled cleanup removes city saves after 30 days of withdrawn permission or 12 months without a cloud save or renewed parent confirmation. Local browser copies and downloads must be removed separately. Cleanup preserves nicknames and other games. Unfinished permission requests expire after 30 days; minimal permission/delivery evidence is retained while active and for up to three years after withdrawal or supersession. Restricted provider backups and security logs follow their own retention schedules.

Providing a child’s real name, email, school, address, photo, or other personal profile information is not required. Permission is optional. Without it, the child cannot use this Cornerstone service.