How to Build gRPC Bidirectional Streaming on Kotlin Multiplatform Without Breaking Production

A technical guide outlines how to implement gRPC bidirectional streaming across a Kotlin Multiplatform project, connecting a Ktor backend to a Compose Multiplatform UI. The approach recommends splitting proto codegen by platform and passing only ByteArray across the common module boundary to avoid compatibility issues with JVM-generated artifacts. Kotlin Flow is used to manage backpressure at the transport layer, with a rendezvous channel preventing unbounded buffering when the server emits faster than the client consumes. A key production risk highlighted is connection pool exhaustion: at 100,000 mobile clients, even a 2% simultaneous reconnect event can generate 2,000 concurrent connection attempts and crash a backend within seconds. The guide recommends exponential backoff with full jitter on the client side, combined with explicit connection age limits on the Ktor server, to keep reconnect load sustainable.