Adding a third person to an encrypted conversation seems like it should be simple. It isn't. The cryptographic properties that make 1:1 messaging secure — forward secrecy, post-compromise security, deniability — become significantly harder to preserve as group size grows. When Signal introduced group chats, they faced a problem that doesn't exist in 1:1 messaging: how do you efficiently encrypt a
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