What it is
Eight players, seven rounds, one shrinking lobby. Everyone gets the same SQL puzzle each round; your query runs against a freshly-seeded in-memory database, and the slowest correct answer is eliminated — last query standing wins. Empty seats fill with bots after eight seconds, so a match always starts, and registered players carry an ELO-style rating that only moves when you're up against real humans.
It's grown a second mode: a single-player campaign where the data is the story — a seven-chapter hacker narrative ("Project Cascade") of dialogue, query puzzles, and boss "ICE" encounters, with a trace meter that punishes brute-forcing and hints that cost you.
How it's built
A pnpm + TypeScript monorepo. React + Vite on the front, with a Monaco editor for real SQL syntax highlighting (lazy-loaded so it doesn't bloat first paint); Fastify + Socket.IO on the back; Prisma + SQLite for persistence; JWT auth for both guests and accounts.
The interesting part — running untrusted SQL safely, in real time
Every submitted query is hostile input. Each round seeds a fresh :memory: SQLite database and runs the query in a worker thread with a hard timeout, so a runaway join or recursive CTE gets killed instead of freezing the match for everyone else. The workers are pooled with backpressure, so a burst of submissions can't exhaust memory. Validation is defense-in-depth — the main thread and the worker each independently enforce SELECT-only, single-statement queries, and the worker is the real trust boundary. Every submission is tagged with its round, so a late answer can't leak into the next one, and a per-user rate limiter survives socket reconnects so you can't refill your quota by bouncing the connection.
Status
The competitive mode is complete and polished, and all seven campaign chapters are playable. The current build is redesigning that campaign into a new beat-driven format with real learning features — mastery tracking, spaced review, cold-solve checks — and tougher boss fights; Chapter 1 is converted and tested, with the rest rolling over one chapter at a time. Closed alpha, not public yet.