We Migrated from REST to gRPC 1.60 and Cut Network Traffic by 40%

After 14 months of running a 12-service microservices fleet on REST/JSON, we migrated to gRPC 1.60 with Protobuf 3.21, cutting total network egress by 40%, reducing p99 API latency from 210ms to 78ms, and saving $22,400 per month in AWS data transfer...