Want to be the founding engineer for a few hours?
Drop into a fictional company on Day 1. Every few months a crisis fires. Make the call. Live with the consequences. The debt you accrue at Month 3 is still there at Month 28.
Each crisis: read the room, pick a call from a few options, defend it to a skeptical CTO, live with the debt. Eleven crises over one season, playable across about five sittings.
Idempotency, audit trails, and blast radius. One corrupt reconciliation report away from losing a bank.
Feed ranking, fan-out, and the moment a celebrity posts and your read replicas fall over.
Latency, presence, and what happens when a streamer drops a code and 400k users arrive in thirty seconds.
Why a season, and not another problem
A problem page asks you to design something well. A season asks you to design something now, with three quarters of context you did not write and a deadline that does not care. Both matter, and only one of them is what the job feels like.
Every option you take is recorded as a diagram version, so the system you end the season with is one you can trace back decision by decision — including the ones you would now make differently.
The debt mechanic
The fast option is usually available and usually correct for the quarter you are in. It also leaves debt, and debt matures: months later a crisis fires because of a call you made, and the game shows you your own diagram and your own journal entry from the day you made it.
Quiet months let you pay some of it down, which is the trade every real team makes and almost no interview asks about.
Defending the call
Picking an option is half of it. A skeptical CTO then asks why — what you gave up, what breaks first, and what you would watch. The answer is scored on whether it engages with the actual trade-off, not on whether it matches a key.
How a season ends
One of three codas — an IPO, an acquisition, or staying private — each of which reads your accumulated debt back to you differently. A due-diligence review is not kind to a shortcut that a growth quarter forgave.
Lab Mode
Replay any crisis in isolation, try every option, and compare consequences side by side. No season, no debt — just study.
Each session takes 20–40 minutes. Your progress is saved locally. No account required.