gRPC & Protocol Buffers

gRPC (gRPC Remote Procedure Calls) is a high-performance, open-source universal RPC framework developed by Google. While REST over HTTP/1.1 with JSON payloads is standard for public internet APIs, using JSON/REST for internal microservice-to-microservice communication introduces massive inefficiencies:

1. JSON Serialization Overhead: JSON is human-readable text. Encoding numbers, field names, and strings into ASCII/UTF-8 requires heavy CPU parsing and string allocation.
2. Payload Size: Repeated JSON keys (e.g., {"user_first_name": "Alice", "user_first_name": "Bob"}) consume massive redundant bandwidth.
3. No Compile-Time Type Safety: REST contracts are loosely enforced, leading to runtime schema mismatches and breaking production changes.
4. No Native Bidirectional Streaming: REST requires polling or WebSockets.

gRPC combines two foundational Google technologies to solve this:

• Protocol Buffers (Protobuf): A language-neutral, platform-neutral binary serialization mechanism that compresses payloads to 15-20% of equivalent JSON size and serializes/deserializes 5x to 10x faster.
• HTTP/2 Transport: Provides binary framing, multiplexing, stream prioritization, and bidirectional streaming out of the box.