Web Dev//backend

Code that runs on a server, not in the browser. If it runs in the browser, it's frontend, regardless of the language. What makes it "backend" is where it executes, not what language it's written in.

Code that runs on a server, not in the browser. If it runs in the browser, it's frontend, regardless of the language. What makes it "backend" is where it executes, not what language it's written in.

Typical responsibilities: API endpoints, database queries, authentication, business logic, file processing

Traditional: a Node.js/Express process running 24/7 on a server, connected to PostgreSQL or another database

Serverless: functions that spin up per request (Lambda, Workers, Vercel Functions)

In Next.js, frontend and backend live in the same project. API Routes are backend code deployed as serverless functions. The full stack in one repo.

In a Vite + React project (like InfraPhysics), there's no backend. Content compiles to static files at build time. Cloudflare Pages serves them. The only server-side logic is an edge function injecting OpenGraph meta tags for crawlers.

The backend is where you connect to PostgreSQL, Pinecone, Supabase, whatever data layer you need. The frontend calls the backend's API.