API Routes

Route handlers

A simple API

// app/api/courses/route.js\nexport async function GET() {\n  const courses = await fetchCourses();\n  return Response.json(courses);\n}

POST with validation

// app/api/enroll/route.js\nexport async function POST(request) {\n  const body = await request.json();\n  if (!body.course_id) {\n    return Response.json({ error: "course_id required" }, { status: 400 });\n  }\n  await enrollUser(body.course_id);\n  return Response.json({ ok: true });\n}

Environment variables

// .env.local (never commit this!)\nDATABASE_URL="mysql://user:pass@host/db"\nAPI_SECRET="…"

Using the API from React

const res = await fetch("/api/enroll", {\n  method: "POST",\n  headers: { "Content-Type": "application/json" },\n  body: JSON.stringify({ course_id: 12 }),\n});

Tip: Keep secrets in .env.local only — anything in process.env prefixed NEXT_PUBLIC_ is visible in the browser.