Next.js

Route Handlers Advanced: Webhooks, CORS & Streaming

28 min Lesson 47 of 80

Route Handlers Advanced: Webhooks, CORS & Streaming

This lesson expands the Next.js path with an advanced topic from the official Next.js documentation. The goal is not only to memorize an option or file name, but to understand its impact on rendering, caching, security, and deployment.

After this lesson you should be able to apply the topic in a real project, choose the right boundary for it, and explain it as a reviewable engineering decision.

Core Concepts

HTTP method exports
raw body verification
CORS headers
streaming responses
API runtime selection

Practical Example

// app/api/webhooks/provider/route.ts
import { headers } from 'next/headers'
import { NextResponse } from 'next/server'

export async function POST(request: Request) {
  const body = await request.text()
  const signature = (await headers()).get('x-signature')
  if (!signature || !verifySignature(body, signature)) {
    return NextResponse.json({ error: 'Invalid signature' }, { status: 401 })
  }
  await handleWebhook(JSON.parse(body))
  return NextResponse.json({ received: true })
}

This lesson is aligned with these official Next.js documentation areas: Route Handlers, NextResponse, and runtime API docs.

Why It Matters

In production applications, this topic affects page speed, data freshness, authorization clarity, and operational reliability after deployment.

Implementation Workflow

Decide whether the data is public or user-specific.
Choose the smallest part of the tree that needs this behavior.
Connect the example to a real route and add a small verification check.
Document the effect on caching and deployment.

Hands-on Practice

Create a payment webhook route that validates a signature before parsing the event payload.

Many webhook providers sign the raw request body, so parsing JSON before verification can break security.

Summary

Judge the implementation by how clear the decision is, whether the behavior is correct after build, and how easily it can be traced in production.