# Protocol Buffers — Language-Neutral Data Serialization by Google

> Protocol Buffers (protobuf) is Google's language-neutral, platform-neutral mechanism for serializing structured data, used extensively in gRPC and microservice communication.

## Install

Save as a script file and run:

# Protocol Buffers — Language-Neutral Data Serialization by Google

## Quick Use
```bash
# Install protoc compiler (macOS)
brew install protobuf

# Or download from GitHub releases
# Define a message in person.proto:
# syntax = "proto3";
# message Person { string name = 1; int32 id = 2; }

# Generate Python code
protoc --python_out=. person.proto

# Generate Go code
protoc --go_out=. person.proto
```

## Introduction
Protocol Buffers (protobuf) is a data serialization format created by Google for inter-service communication. It defines a schema in `.proto` files and generates strongly typed code for over a dozen languages, producing compact binary payloads that are smaller and faster to parse than JSON or XML.

## What Protocol Buffers Does
- Defines structured data schemas in a language-agnostic `.proto` IDL
- Generates serialization and deserialization code for C++, Java, Python, Go, Rust, and more
- Produces compact binary encoding that reduces payload size compared to text formats
- Supports schema evolution with backward and forward compatibility via field numbering
- Serves as the default wire format for gRPC remote procedure calls

## Architecture Overview
A `.proto` file declares message types with numbered fields and scalar or composite types. The `protoc` compiler reads these definitions and, through language-specific plugins, emits source code containing builder, accessor, and codec methods. At runtime the generated code serializes objects into a tag-length-value binary format and deserializes them back, skipping unknown fields for forward compatibility. Reflection and descriptor APIs allow dynamic inspection of schemas at runtime.

## Self-Hosting & Configuration
- Install `protoc` from the official GitHub releases or via system package managers
- Place `.proto` files in a shared repository or use Buf Schema Registry for team workflows
- Use `protoc-gen-go`, `protoc-gen-python`, or other plugins for target language output
- Integrate `protoc` into build pipelines via Bazel rules, Gradle plugins, or Makefiles
- Adopt Buf CLI for linting, breaking-change detection, and code generation management

## Key Features
- Compact binary encoding is 3-10x smaller and 20-100x faster than XML
- Strongly typed code generation catches schema mismatches at compile time
- Field numbering enables adding or removing fields without breaking existing clients
- First-class support in gRPC for building high-performance RPC services
- Mature ecosystem with editions, proto2, and proto3 syntax variants

## Comparison with Similar Tools
- **JSON** — human-readable but larger payloads and no schema enforcement
- **MessagePack** — binary JSON, compact but lacks schema and code generation
- **Apache Avro** — schema-embedded format popular in Hadoop, uses JSON schemas
- **FlatBuffers** — zero-copy access for game engines but more complex API
- **Cap'n Proto** — zero-copy with RPC support but smaller ecosystem than protobuf

## FAQ
**Q: Can I use protobuf without gRPC?**
A: Yes. Protobuf is a standalone serialization library. gRPC uses it as the default codec, but you can serialize protobuf messages to files, queues, or any transport.

**Q: Is protobuf human-readable?**
A: The binary format is not human-readable. Use `protoc --decode` or the text-format representation for debugging. For human-readable needs, JSON mapping is supported.

**Q: How does schema evolution work?**
A: Each field has a unique number. New fields can be added and old ones removed without breaking existing code, as long as field numbers are not reused.

**Q: Which languages are supported?**
A: Official support includes C++, Java, Python, Go, C#, Ruby, Objective-C, PHP, Dart, and Kotlin. Community plugins cover Rust, Swift, TypeScript, and others.

## Sources
- https://github.com/protocolbuffers/protobuf
- https://protobuf.dev/

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Source: https://tokrepo.com/en/workflows/8ce3365e-4491-11f1-9bc6-00163e2b0d79
Author: Script Depot