API Route Handlers

Requirements

Build a GET/POST route handler in Next.js (`/api/feedback/route.ts`). The handler must validate the POST body (requires an email and message), return a 400 Bad Request error if validation fails, and return a 201 Created response on success.

Expected Output

A Next.js API route handler script handling payload assertions and returning status codes.

Hints & Tips

1Use `NextRequest` and `NextResponse` imports.
2Catch JSON parsing failures within try-catch blocks to prevent server crashes.
3Check POST body fields: reject empty strings.

Senior Code Review Checklist

0 / 4 Checked

Common Architectural Mistakes

1Returning plain status codes without JSON bodies, making debugging hard.
2Forgetting to wrap request parsing in try-catch blocks, leading to unhandled server errors on empty payloads.
3Omitting CORS headers if API calls cross domains.

Developer Solution

Click to toggle the recommended code solution

Architectural Explanation

The API handler imports Next server classes, parses inputs inside try-catch blocks, validates the inputs, and returns appropriate HTTP status codes.

Code Snippet

typescript

import { NextRequest, NextResponse } from "next/server";

export async function POST(req: NextRequest) {
  try {
    const body = await req.json();
    const { email, message } = body;

    if (!email || !email.includes("@") || !message) {
      return NextResponse.json(
        { error: "Valid email and message parameters are required." },
        { status: 400 }
      );
    }

    return NextResponse.json(
      { success: true, message: "Feedback submitted successfully." },
      { status: 201 }
    );
  } catch (error) {
    return NextResponse.json(
      { error: "Malformed request payload." },
      { status: 400 }
    );
  }
}

Explain in Interview

How to pitch this solution during technical interviews

I compile route handlers using App Router API folders. I parse incoming payloads inside try-catch scopes to prevent crashes, validate body fields against Zod schemas, and issue standardized JSON error payloads and HTTP status codes.

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Requirements

Expected Output

A Next.js API route handler script handling payload assertions and returning status codes.

import { NextRequest, NextResponse } from "next/server"; export async function POST(req: NextRequest) { try { const body = await req.json(); const { email, message } = body; if (!email || !email.includes("@") || !message) { return NextResponse.json( { error: "Valid email and message parameters are required." }, { status: 400 } ); } return NextResponse.json( { success: true, message: "Feedback submitted successfully." }, { status: 201 } ); } catch (error) { return NextResponse.json( { error: "Malformed request payload." }, { status: 400 } ); } }