Web Dev//API

Application Programming Interface. A contract between two pieces of software: "send me this request, I'll give you this response." In web dev, almost always means HTTP endpoints that return JSON.

Application Programming Interface. A contract between two pieces of software: "send me this request, I'll give you this response." In web dev, almost always means HTTP endpoints that return JSON.

External APIs: third-party services your app calls via HTTP (Google, Stripe, Sentry, etc.)

Event-driven APIs: your app fires an event, processing happens asynchronously in a job queue

Internal APIs: your own backend endpoints that your frontend calls

In Next.js, API Routes define your internal API — deployed as Vercel Functions