How the Internet Works (Client-Server)
The internet is a network of millions of connected computers where every conversation has two roles: the client (your browser/app) sends a REQUEST, the server (a computer running 24/7) sends a RESPONSE. Why: your entire stack is client-server — the Android app is a client, Supabase is a server, your future Spring Boot backend is your own server. Without this model, debugging "why isn't the data arriving" is impossible. When: whenever your app pulls data from a server, whenever you see "no connection," whenever you decide which side to write logic on. How: the client sends a request to the server's address → the server processes it (often reading from a database) → returns a response → the client displays it. Where: browser, your APK, Postman = clients; Supabase, your future Spring Boot = servers. Who: every developer — you, on both sides, because you'll write both client and server code.