Chapter 23: Protobuf Style Guide and API Design

File Organization

// One service per file, messages can be split or co-located
// Package = company.product.version
syntax = "proto3";
package mycompany.users.v1;
option go_package = "github.com/mycompany/users/v1;usersv1";

Naming Rules

• Files: lower_snake_case.proto
• Messages/Enums: PascalCase
• Fields: lower_snake_case
• RPCs: PascalCase (verb + noun: CreateUser, ListOrders)
• Enum values: UPPER_SNAKE_CASE with type prefix: STATE_ACTIVE

Field Number Best Practices

• 1-15: use for most frequent fields (1 byte to encode)
• 16-2047: less frequent fields (2 bytes)
• Never skip numbers unnecessarily
• Reserve removed field numbers forever

Mark as Complete