Protobuf
Protocol Buffers (Protobuf) is Google’s language-neutral binary serialization format. You define message schemas in .proto files, and the compiler generates strongly-typed serialization code in your language of choice. The binary encoding is significantly smaller and faster to parse than JSON, making it the default wire format for gRPC-based services.
The tradeoff is observability: binary payloads aren’t human-readable without tooling, which complicates debugging and log inspection. For this reason Protobuf is best suited to high-throughput internal service-to-service communication where performance matters — not for public-facing APIs or anywhere humans need to read the wire format directly.
Blurb
Protocol Buffers are Google’s language-neutral, platform-neutral, extensible mechanism for serializing structured data — think XML, but smaller, faster, and simpler.
Summary
Trial Protobuf when you have a performance bottleneck on an internal API boundary and are already using or considering gRPC. The schema-first approach enforces strong contracts between services and code generation eliminates serialization bugs. However, the operational overhead (proto file management, generated code, binary debugging) is real — don’t reach for it when JSON + REST is sufficient. Pairs naturally with gRPC; less useful without it.