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.