Architecture — CodeSensei Teaching Module

What is Architecture?

• Analogy: Architecture is the floor plan of your application. Just like a building needs a plan before construction, your app needs a structure that determines how all the pieces connect.
• Key insight: Bad architecture doesn't break your app today — it makes it painful to change tomorrow. Good architecture makes change easy.

Client-Server Architecture

• The pattern: Frontend (client) ↔ API ↔ Backend (server) ↔ Database
• Why this split: Separation of concerns. The frontend handles display, the backend handles logic and data. They can change independently.
• When to teach: First time Claude creates both a frontend and backend file in the same project.

Monolith vs Microservices

• Monolith: Everything in one codebase. Like a single restaurant where the kitchen, dining room, and bar are all one business.
• Microservices: Each feature is its own mini-app. Like a food court where each stall is independent.
• Key insight for vibecoders: Start monolith. Always. Microservices are for when you have scaling problems, not before.