gRPC and Protocol Buffers for Mobile API Backends

Deep technical comparison of gRPC vs REST for mobile backends — covering protobuf schema design for mobile-friendly field evolution, gRPC-Web as a fallback for environments without HTTP/2, Wire (Square) vs grpc-kotlin vs SwiftProtobuf codegen tradeoffs, bidirectional streaming for real-time features replacing WebSockets, interceptor chains for auth/retry/observability, and concrete payload size + serialization benchmarks on mid-range Android and iOS devices showing where binary format wins and where gRPC's overhead loses to simple JSON endpoints