Reactjs – Nextjs API routing issue

Problem:

I am new to Next.js and trying to implement API routing using the latest version (Next.js 15) with the app-based routing system. However, I keep getting a 404 Not Found error when trying to access the GET API or when making a POST request.

File Structure:

src/
  app/
    api/
      transform/
        route.js
    page.js

Code:

API Route (src/app/api/transform/route.js)

import { NextResponse } from 'next/server';

export async function GET() {
  return NextResponse.json({ message: "Hello from transform API" });
}

export async function POST(request) {
  try {
    // Your logic here
  } catch (error) {
    return NextResponse.json({ error: error.message }, { status: 500 });
  }
}

export const runtime = 'nodejs'; // Using Node.js runtime

API Call (src/app/page.js)

const handleTransform = async () => {
  if (!apiKey || !resume || !jobDescription) {
    alert('Please provide all required information');
    return;
  }

  try {
    const formData = new FormData();
    formData.append('resume', resume);
    formData.append('jobDescription', jobDescription);
    formData.append('apiKey', apiKey);

    const response = await fetch('/api/transform', {
      method: 'POST',
      body: formData,
    });

    const data = await response.json();
    if (!response.ok) throw new Error(data.message);

    setTransformedResume(data.transformedResume);
    setAtsScore(data.score);
  } catch (error) {
    console.error(error);
    alert('Transformation failed. Please try again.');
  }
};

Environment:

• Next.js Version: 15
• Runtime: Node.js
• API Location: src/app/api/transform/route.js
• API Call: src/app/page.js

What I’ve Tried:

1. Verified the file path is correct (src/app/api/transform/route.js).
2. Ensured that app directory-based routing is enabled.
3. Set the runtime to Node.js explicitly (export const runtime = 'nodejs').

Expected Behavior:

The GET endpoint should return:

{ "message": "Hello from transform API" }

And the POST request should execute without issues.

Question:

What am I doing wrong, and how can I fix the 404 error for my API routes?