web dev//backend

The backend is the code that runs on a server rather than in the browser. Code that runs in the browser is frontend whatever its language: what places code in the backend is where it executes.

The backend is the code that runs on a server rather than in the browser. Code that runs in the browser is frontend whatever its language: what places code in the backend is where it executes.

Its typical responsibilities are API endpoints, database queries, authentication, business logic and file processing; slow work goes to a job queue and recurring work to a cron job, so requests stay fast. The traditional form is a Node.js or Express process running around the clock on a server, connected to PostgreSQL or another database; the serverless form is 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.