Inside the Kitchen

Narrated

Last lesson, we split your app into a front door and a kitchen. The front door is the page people see. The kitchen is the backend, the part that holds your API key, calls the AI, and does the real work where nobody can peek.

But here’s a question we walked right past: who is cooking in that kitchen?

When Claude Code built your backend, it used something called Next.js API routes. That just happened. You asked for a backend, Next.js came with one built in, so that’s what you got. It was the right call. It kept everything in one project, one language, one place to look. For a first app, that simplicity is gold.

Except “it came with one” is not the same as “you chose one.” And as the architect, choosing is your job. A backend is not a single fixed thing. It’s a decision. Restaurants don’t all run the same kitchen. A tiny cafe, a sushi bar, and a stadium that feeds forty thousand people on game day all have kitchens, but they are not remotely the same kitchen, because they are not solving the same problem.

This lesson is about the kitchen itself. What a backend actually is, why Next.js is the right one to start with, and the other kitchens you would walk into as your app grows up.