How Swiggy Migrated from protobuf-java to Square Wire

Summary

Swiggy migrated from protobuf-java to Square Wire after profiling showed that the runtime and protoc-generated code consumed 6.735 MB of Android app size. protobuf-javalite was rejected because Swiggy relies extensively on google.protobuf.Any, while Wire retained support for Any and other well-known types with a smaller runtime and immutable Kotlin models. The migration required updating snake_case property access, message construction, serialization calls, ProGuard rules, and a custom pipeline that compiled all schemas together before publishing package-specific AARs to AWS CodeArtifact. The team also fixed repeated enum fields with [packed = true] after discovering a silent wire-format mismatch. It reduced Swiggy’s app size by 3.52 MB and produced measurable reductions for Instamart and Toing.

Takeaways

1. 1

   Wire generates immutable Kotlin models with constructors and copy(), replacing protobuf-java’s Java builders and reducing generated-code overhead.

2. 2

   Repeated enum fields required an explicit [packed = true] annotation in the .proto files because Wire otherwise encoded them unpacked, causing silent wire-format mismatches.

3. 3

   R8 rules must preserve Wire’s reflective ADAPTER fields, @WireField annotations, enum fromValue(int) methods, and selected Companion names for JSON serialization to work.