03 · Four things that will not change
Every skill, every problem, every hint and every mode, with no paywall on practice now or later. If we ever charge for anything it will be for tooling around the free thing, like a class view for a teacher, and the free thing will stay exactly as it is. This is going into the charter of the public benefit corporation we are forming, which makes it the reason the company exists rather than a policy it could change.
There are no accounts, no analytics scripts, no cookies, and no requests to anyone but the server that hands you the page. Your progress lives in your browser and nowhere else, and asking for a hint is between you and the problem. The whole privacy policy fits on one short page, and it says that anything beyond what it describes would be a change to the charter, not a setting someone could flip.
There is no score that drops when you miss, no streak to lose, and no mastery that gets taken back. A miss is grey rather than red, and it tells you why. The only things that move are the difficulty, which you can see and control, and your count of problems solved, which only goes up.
No hearts, no leagues, no mascots, no confetti. The research on those is weak to negative, and we think people can tell when a product is trying to manage them. What makes this hard to put down is the problem in front of you, feedback that arrives the instant you submit, and the next problem being just hard enough. The things we do call games are the same problems in a different shape, and the only score in any of them is your own best.