I Got 15K People to Practice SQL by Turning Them Into Detectives

SQL practice is boring because you're querying meaningless data in a vacuum. I built SQL Case Files - a detective game where you solve crimes by writing real SQL queries. Your phone vibrates when you close a case. No badges, no streaks, just investigations that feel physical. 15K monthly users in 4 weeks. This is how I made it work technically: SQLite WASM for local execution, result-set validation instead of SQL text matching, mobile-first UX with sticky schemas and bottom-sheet drawers, and a rate-limited AI assistant (20 calls/day because I'm paying for it). The constraint accidentally made people better at SQL. Free to play, no signup, runs entirely in your browser.