The first AI feature I shipped on a flat plan lost money on the third user who discovered it. Not slowly. Immediately. He was running a script through it on a loop because the UI did not stop him from doing that, and his single account burned through more in API costs that week than the feature was supposed to make in a month. I shipped the fix on a Sunday and rewrote the pricing on a Tuesday, and
At 3:17 AM on a Tuesday in Q3 2024, our production Kotlin 2.0 microservice fleet hit a 92% memory utilization threshold across 140 nodes, traced to a silent coroutine leak in Ktor 2.2’s request pipeline that had been bleeding 12MB of heap per second for 72 hours. We lost $14k in SLO credits before we found the root cause. A Couple Million Lines of Haskell: Production Engineering at Mercury (78 p