nextjs-api-file-upload

name	nextjs-api-file-upload
description	For Next.js App Router, use request.formData() and stream/parse the file (e.g. CSV) in the route handler. Do not use Express-style middleware (e.g. multer) in API routes—it can block the request pipeline and cause hangs. Use when implementing file upload in Next.js API routes.

Next.js API File Upload (App Router)

This project uses Next.js App Router. File upload in API routes must use Next.js built-in handling, not Express middleware.

Do Not Use

• Express middleware (e.g. multer) in API routes. It can block the request pipeline and cause long hangs (e.g. login or upload appearing stuck).

Do Use

• request.formData() in the route handler.
• Stream or parse the file (e.g. CSV) inside the handler after calling formData().

Example Pattern

// In app/api/upload/route.ts (or similar)
export async function POST(request: Request) {
  const formData = await request.formData();
  const file = formData.get('file') as File | null;
  if (!file) return .({ :  }, { :  });
  
  
}