architecture

# 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. ## MVC Pattern - **Model** — the data layer (what your app knows) - **View** — the display layer (what the user sees) - **Controller** — the logic layer (what happens when the user does something) - **Analogy:** A restaurant. The menu (model) has the dishes. The table presentation (view) is what the customer sees. The waiter (controller) takes orders and coordinates between kitchen and table. ## State Management - **The problem:** As your app grows, keeping track of data that multiple components need becomes messy. - **Analogy:** In a small office, everyone shouts across the room. In a big company, you need an organized messaging system (Slack, email). - **Solutions:** React Context, Redux, Zustand — all solve the same problem differently. ## Caching - **Analogy:** Instead of cooking every meal from scratch, you prep common ingredients in advance. Caching stores frequently-used data closer to where it's needed so you don't have to fetch it every time. ## Authentication vs Authorization - **Authentication:** "Who are you?" (login) - **Authorization:** "What are you allowed to do?" (permissions) - **Analogy:** Authentication is the bouncer checking your ID. Authorization is the VIP list determining which areas you can access. ## When to Teach Architecture - Only for Blue Belt and above — beginners should focus on making things work before worrying about structure - Introduce naturally when Claude makes an architectural choice the user might wonder about